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Objective: Breastfeeding improves cognitive ability in childhood, but the long-term impact on socioeconomic outcomes remains unknown. We examined associations between durations of predominant and any breastfeeding and educational attainment, income, and labor force participation in adulthood, and whether these varied by maternal education., Study Design: Prospective cohort study., Methods: We followed 84,255 individuals born 1959-1967 with prospectively collected information on breastfeeding duration and intensity from the Copenhagen Infant Health Nurse Records. Socioeconomic outcome information came from national registers (1980-2020). Linear and Poisson regression were used, and models were adjusted for prenatal and postnatal variables across three levels of maternal education., Results: Durations of being breastfed exhibited associations with all outcomes, with most being more pronounced among mothers with low education. Compared with infants breastfed <1 month, those breastfed ≥5 months had 0.68 (95% confidence interval: 0.60-0.76), 0.55 (0.45-0.65), and 0.65 (0.46-0.84) additional years of education for infants born to mothers with low, medium, or high education, respectively. Moreover, infants breastfed ≥5 months had 4047, 3713, and 1902 US$ higher annual incomes and were 23% less likely to be outside the labor force at age 50 years. These associations were stronger with longer breastfeeding durations and for predominant than any breastfeeding., Conclusions: Prolonged and higher breastfeeding intensity consistently exhibited dose-dependent associations with improved socioeconomic indicators in adulthood. Notably, these relationships were more pronounced among individuals whose mothers had lower educational attainment. Consequently, our findings suggest that breastfeeding may have a lasting positive influence on socioeconomic outcomes, particularly for the most disadvantaged infants., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Body mass index (BMI) is used to screen for under- or overweight. However, it is unknown whether BMI-screening in school children reduces the incidence of overweight and obesity. We aimed to summarise the knowledge on positive and negative consequences on BMI and weight-related perceptions and behaviours of BMI-screening followed by an intervention to prevent and/or address obesity. We performed a systematic literature search, April 2023, using the PubMed, ScienceDirect and Google Scholar databases. We included randomised controlled trials and observational studies, including children aged 6 to 18 years and examining BMI-screening in a school setting. The primary outcome measures were BMI and weight status. Secondary outcome measures were weight-related perceptions and behaviours. Three studies met the inclusion criteria; two randomised controlled trials and one observational study. All studies used BMI-screening followed by sending report cards to the parents. None of the studies found a change in BMI z-scores in school children. Screening could cause transitory body-dissatisfaction and increase peer weight talk, yet potentially reduce problematic weight behaviours like skipping meals or excessive dieting. Reporting BMI to parents may influence their perception of their children's weight status, but does not change behaviour. The sparse evidence available suggested that BMI screening followed by sending report cards to parents does not change BMI z-scores among children in primary, middle and high school. Studies using appropriate evidence-based weight management interventions as a follow-up are lacking. Such studies may improve future prevention, detection and treatment of weight-related issues., (© 2024 World Obesity Federation.)

Background: Being breastfed has established benefits for infant health, but its long-term effects on adult diseases, including cancer, remain underexplored. We examined associations between being breastfed in infancy and the risks of common cancers., Methods: Data from 339,115 participants (191,117 women) enrolled in the UK Biobank with self-reported breastfeeding data were linked to national cancer registries. Cox models estimated sex-specific hazard ratios (HR) and 95% confidence intervals (CI) for the associations between being breastfed (ever/never) and risks of overall cancer as well as common cancer sites., Results: In total, 34,392 incident cancers (17,895 in women) were registered. The HR of overall cancer associated with being breastfed was 1.05 (95% CI 1.01-1.09) in women and 1.00 (95% CI 0.96-1-04) in men. In site-specific analysis being breastfed was associated with an increased risk of breast and ovarian cancer in women and a reduced risk of oesophageal cancer in men., Discussion: We found that having been breastfed was associated with a marginally increased risk of adult cancer in women, but we found no evidence of an association in men. These findings should be viewed within the study limitations, and do not outweigh the many benefits that breastfeeding provides., (© 2024. The Author(s).)

Aim: To examine trends in all body mass index (BMI) groups in children from 1936 to 2011., Methods: We included 197 694 girls and 201 276 boys from the Copenhagen School Health Records Register, born between 1930 and 1996, with longitudinal weight and height measurements (6-14 years). Using International Obesity Task Force criteria, BMI was classified as underweight, normal-weight, overweight and obesity. Sex- and age-specific prevalences were calculated., Results: From the 1930s, the prevalence of underweight was stable until a small increase occurred from 1950 to 1970s, and thereafter it declined into the early 2000s. Using 7-year-olds as an example, underweight changed from 10% to 7% in girls and from 9% to 6% in boys during the study period. The prevalence of overweight plateaued from 1950 to 1970s and then steeply increased from 1970s onwards and in 1990-2000s 15% girls and 11% boys at 7 years had overweight. The prevalence of obesity particularly increased from 1980s onwards and in 1990-2000s 5% girls and 4% boys at 7 years had obesity. These trends slightly differed by age., Conclusion: Among Danish schoolchildren, the prevalence of underweight was greater than overweight until the 1980s and greater than obesity throughout the period. Thus, monitoring the prevalence of childhood underweight remains an important public health issue., (© 2023 The Authors. Acta Paediatrica published by John Wiley & Sons Ltd on behalf of Foundation Acta Paediatrica.)

Background: The early life factors of birthweight, child weight, height, body mass index (BMI) and pubertal timing are associated with risks of breast cancer. However, the predictive value of these factors in relation to breast cancer is largely unknown. Therefore, using a machine learning approach, we examined whether birthweight, childhood weights, heights, BMIs, and pubertal timing individually and in combination were predictive of breast cancer., Methods: We used information on birthweight, childhood height and weight, and pubertal timing assessed by the onset of the growth spurt (OGS) from 164,216 girls born 1930-1996 from the Copenhagen School Health Records Register. Of these, 10,002 women were diagnosed with breast cancer during 1977-2019 according to a nationwide breast cancer database. We developed a feed-forward neural network, which was trained and tested on early life body size measures individually and in various combinations. Evaluation metrics were examined to identify the best performing model., Results: The highest area under the receiver operating curve (AUC) was achieved in a model that included birthweight, childhood heights, weights and age at OGS (AUC = 0.600). A model based on childhood heights and weights had a comparable AUC value (AUC = 0.598), whereas a model including only childhood heights had the lowest AUC value (AUC = 0.572). The sensitivity of the models ranged from 0.698 to 0.760 while the precision ranged from 0.071 to 0.076., Conclusion: We found that the best performing network was based on birthweight, childhood weights, heights and age at OGS as the input features. Nonetheless, this performance was only slightly better than the model including childhood heights and weights. Further, although the performance of our networks was relatively low, it was similar to those from previous studies including well-established risk factors. As such, our results suggest that childhood body size may add additional value to breast cancer prediction models., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Svendsen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Primary prevention targets development of overweight in individuals with healthy weight and is a great challenge. This paper summarizes the main findings of a working group of the Danish Council on Health and Disease Prevention that reviewed the literature on primary prevention of overweight and obesity among children and adolescents. The results were presented in a Danish report, in which a 2019 Cochrane review on childhood obesity prevention was complemented by searches in PubMed to include all relevant subsequent studies published from January 2018 until March 2020. In this paper, the review was updated until June 2023. Numerous childhood overweight prevention interventions have been developed during the past decades, primarily targeting diet and/or physical activity. Several of these interventions showed positive effects on diet and physical activity level but did not show effects on risk of developing overweight. The evidence foundation is inconsistent as four out of five interventions did not show positive effects. Previously observed intervention effects may not reflect excessive weight gain prevention among children with healthy weight but rather bodyweight reduction among those with overweight or obesity. We do not have sufficient knowledge about how to prevent children with healthy weight from developing overweight, and creative solutions are urgently needed., (© 2023 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.)

Worldwide, far too many children and adolescents are living with the disease of obesity. Despite decades of public health initiatives, rates are still rising in many countries. This raises the question of whether precision public health may be a more successful approach to preventing obesity in youth. In this review, the objective was to review the literature on precision public health in the context of childhood obesity prevention and to discuss how precision public health may advance the field of childhood obesity prevention. As precision public health is a concept that is still evolving and not fully identifiable in the literature, a lack of published studies precluded a formal review. Therefore, the approach of using a broad interpretation of precision public health was used and recent advances in childhood obesity research in the areas of surveillance and risk factor identification as well as intervention, evaluation and implementation using selected studies were summarized. Encouragingly, big data from a multitude of designed and organic sources are being used in new and innovative ways to provide more granular surveillance and risk factor identification in obesity in children. Challenges were identified in terms of data access, completeness, and integration, ensuring inclusion of all members of society, ethics, and translation to policy. As precision public health advances, it may yield novel insights that can contribute to strong policies acting in concert that ultimately lead to the prevention of obesity in children., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Associations of birthweight, childhood body size and pubertal timing with breast cancer risks by menopausal status and tumor receptor subtypes are inconclusive. Thus, we investigated these associations in a population-based cohort of Danish women., Methods: We studied 162,419 women born between 1930 and 1996 from the Copenhagen School Health Records Register. The register includes information on birthweight, measured childhood weights and heights at the age of 7-13 years, and computed ages at the onset of the growth spurt (OGS) and at peak height velocity (PHV). The Danish Breast Cancer Cooperative Group database provided information on breast cancer (n = 7510), including estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2) and menopausal status. Hormone replacement therapy use came from the Danish National Prescription Registry. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated by Cox regression., Results: We found that birthweight was not associated with any breast cancer subtypes. While childhood BMI was not statistically significantly associated with ER+ tumors nor consistently with ER- tumors among pre-menopausal women, consistent inverse associations were found among postmenopausal women. At the age of 7 years, the HRs for postmenopausal ER+ and ER- tumors were 0.90 (95% CI 0.87-0.93) and 0.84 (95% CI 0.79-0.91) per BMI z-score, respectively. Similarly, childhood BMI was inversely associated with pre- and postmenopausal HER2- tumors, but not with HER2+ tumors. Childhood height was positively associated with both pre- and postmenopausal ER+ tumors, but not with ER- tumors. At the age of 7 years, the HRs for postmenopausal ER+ and ER- tumors were 1.09 (95% CI 1.06-1.12) and 1.02 (95% CI 0.96-1.09) per height z-score, respectively. In general, childhood height was positively associated with HER2+ and HER2- tumors among pre- and postmenopausal women. Ages at OGS and PHV were not associated with any breast cancer subtypes., Conclusions: We showed that a high BMI and short stature in childhood are associated with reduced risks of certain breast cancer subtypes. Thus, childhood body composition may play a role in the development of breast cancer., (© 2022. The Author(s).)

Aims: We examined associations between five body mass index (BMI) trajectories from ages 6-15 years and register-based adult-onset type 2 diabetes mellitus (T2D) and coronary heart disease (CHD) with and without adjustment for adult BMI., Methods: Child and adult BMI came from two Danish cohorts and 13,205 and 13,438 individuals were included in T2D and CHD analyses, respectively. Trajectories were estimated by latent class modelling. Incidence rate ratios (IRRs) were estimated with Poisson regression., Results: In models without adult BMI, compared to the lowest trajectory, among men the T2D IRRs were 0.92 (95 %CI:0.77-1.09) for the second lowest trajectory and 1.51 (95 %CI:0.71-3.20) for the highest trajectory. The corresponding IRRs in women were 0.92 (95 %CI:0.74-1.16) and 3.58 (95 %CI:2.30-5.57). In models including adult BMI, compared to the lowest trajectory, T2D IRRs in men were 0.57 (95 %CI:0.47-0.68) for the second lowest trajectory and 0.26 (95 %CI:0.12-0.56) for the highest trajectory. The corresponding IRRs in women were 0.60 (95 %CI:0.48-0.75) and 0.59 (95 %CI:0.36-0.96). The associations were similar in direction, but not statistically significant, for CHD., Conclusions: Incidence rates of adult-onset T2D were greater for a high child BMI trajectory than a low child BMI trajectory, but not in models that included adult BMI., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

A high childhood body mass index (BMI) may be protective against benign breast disease (BBD), but little is known about the effects of other early life body size measures. Thus, we examined associations between birthweight, childhood BMI, height, and pubertal timing and BBD risks. We included 171,272 girls, born from 1930 to 1996, from the Copenhagen School Health Records Register, which contains information on birthweight, childhood anthropometry (7-13 years), age at onset of the growth spurt (OGS), and peak height velocity (PHV). During follow-up, 9361 BBD cases (15-50 years) were registered in the Danish National Patient Register. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated by Cox regressions. At all childhood ages, BMI was inversely but non-linearly associated with BBD. The association was slightly stronger in magnitude for BMI z-scores above 0 (HR age 7  = 0.86; 95%CI: 0.83-0.90 per z-score) than below 0 (HR age 7  = 0.95; 95%CI 0.91-0.99 per z-score). Associations between childhood height and BBD differed by age; at 7 years the association was an inverted U-shape, whereas at 13 years height was not associated with BBD. Ages at OGS and PHV were positively associated with BBD. Low and high birthweights were associated with lower BBD risks.   Conclusion: A high childhood BMI, a short or tall stature at young childhood ages, an early pubertal onset, and low or high birthweights are associated with reduced risks of BBD. These complex associations suggest that the role of these factors in breast tissue development during early life warrants further investigation in relation to BBD etiology. What is Known: • Benign breast disease (BBD) is common and may be an intermediary marker of breast cancer risks. • Early life body size may relate to the development of BBD, but currently little is known. What is New: • Girls with a high body mass index at school ages or with an early pubertal timing have decreased risks of BBD. • Short and tall heights at young childhood ages and low and high birthweights are associated with lower BBD risks., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To investigate associations between infant weight gain trajectories and coronary heart disease (CHD)., Study Design: We followed 3645 Danish individuals born between 1959 and 1961 with information on weight at birth and at age 2 weeks and 1, 2, 3, 4, 6, or 12 months. Sex-specific weight trajectories were generated using latent class modeling. Cases of CHD (n = 279) were identified from national health registers. Hazard ratios (HRs) were estimated by Cox regression with sequential adjustment for sex, socioeconomic status, prepregnancy body mass index, maternal smoking, preterm birth, parity, and birth weight., Results: We identified 5 trajectories of weight development in infancy in our cohort: very low-moderate increase (11.5% of the population), low-marked increase (13.9%), low-stable increase (32.4%), average-stable increase (29.8%), and high-moderate increase (12.4%). Compared with the average-stable increasing trajectory, having a very low-moderately increasing weight trajectory in infancy was associated with a higher frequency of adult CHD (HR, 1.56; 95% CI, 1.04-2.33). The higher frequency remained after adjustment for maternal factors but was slightly attenuated after additional adjustment for preterm birth and parity (HR, 1.41; 95% CI, 0.91-2.23) and disappeared after adjustment for birth weight (HR, 0.78; 95% CI, 0.44-1.37). The associations with CHD did not differ between the other trajectories and the average-stable increasing trajectory., Conclusions: Although a pattern of very low-moderate increasing weight during infancy was associated with a higher frequency of adult CHD, the association did not persist after adjustment for birth weight, highlighting the importance of prenatal exposures., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: It remains unknown whether maternal early life body size and changes in height and BMI from childhood to pregnancy are associated with risks of having a preterm delivery., Objectives: We investigated whether a woman's birth weight, childhood height, BMI, and changes in height and BMI from childhood to pregnancy were associated with preterm delivery., Methods: We studied 47,947 nulliparous women born from 1940 to 1996 who were included in the Copenhagen School Health Records Register with information on birth weight and childhood heights and weights at ages 7 and/or 13 years. Gestational age was obtained from the Danish Birth Register, as was prepregnancy BMI, for 13,114 women. Deliveries were classified as very (22 to <32 weeks) or moderately (32 to <37 weeks) preterm. Risk ratios (RRs) and 95% CIs were estimated using binomial regression., Results: A woman's birth weight and childhood height were inversely associated with having very and moderately preterm delivery. Childhood BMI had a U-shaped association with having a very preterm delivery; at age 7 years, compared to a BMI z score of 0, the RRs were 1.31 (95% CI, 1.11-1.54) for a z score of -1 and 1.18 (95% CI, 1.01-1.38) for a z score of +1. Short stature in childhood and adulthood was associated with higher risks of very and moderately preterm delivery. Changing from a BMI at the 85th percentile at 7 years (US CDC reference) to a prepregnancy BMI of 22.5 kg/m2 was associated with RRs of 1.12 (95% CI, 0.91-1.37) and 0.88 (95% CI, 0.78-0.99) for very and moderately preterm delivery, respectively, compared to a reference woman at the 50th percentile at 7 years (22.5 kg/m2 prepregnancy BMI)., Conclusions: Maternal birth weight, childhood height, and BMI are associated with very and moderately preterm delivery, although in different patterns. Consistent short stature is associated with very and moderately preterm delivery, whereas normalizing BMI from childhood to pregnancy may reduce risks of having a very preterm delivery., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Body mass index (BMI) at child and adolescent ages is positively associated with adult coronary heart disease (CHD) whereas height at these ages may be inversely associated with CHD. However, potential effects of age, sex, and socioeconomic status on associations between BMI and CHD are less investigated. We conducted a systematic review and meta-analysis of BMI and height at ages 2-19 years in relation to adult CHD and examined effects of age, sex, socioeconomic status, and other factors. Twenty-two studies on BMI and five on height were included, comprising 5,538,319 individuals and 69,830 CHD events. Random effects meta-analyses were conducted. Child and adolescent BMI were positively associated with CHD (hazard ratio = 1.12; 95% confidence interval [CI] [1.01, 1.25] per standard deviation [SD]), and categorical analyses supported these findings. The associations did not significantly differ by age, sex, or by adjustment for socioeconomic status. Child and adolescent height were inversely associated with CHD (hazard ratio = 0.87; 95% CI [0.81, 0.93] per SD), and categorical analyses agreed. Insufficient studies on height precluded subgroup analyses. Heterogeneity was generally high in all analyses. We found that BMI in youth is positively associated with adult CHD regardless of sex or adjustment for socioeconomic status whereas height is inversely associated with later risk of CHD., (© 2021 World Obesity Federation.)

Introduction: Adult obesity is linked with polycystic ovary syndrome (PCOS), but the importance of body size at ages before PCOS is diagnosed is unknown., Objective: To investigate associations between a woman's own birthweight, childhood body mass index (BMI), height and growth patterns in relation to her risk of PCOS., Methods: We included 65,665 girls from the Copenhagen School Health Records Register, born in the period 1960-1996, with information on birthweight and measured weight and height at the ages of 7-13 years. Overweight was defined using International Obesity Task Force (IOTF) criteria. From the Danish National Patient Register, 606 women aged 15-50 years were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox regression analysis., Results: Birthweight was not associated with PCOS. At the age of 7-13 years, girls with overweight had a higher risk of developing PCOS than girls without overweight; HR 2.83 (95% CI 2.34-3.42) at age 7 years and 2.99 (95% CI 2.38-3.76) at age 13 years. Furthermore, girls with overweight at both 7 and 13 years had a higher risk of developing PCOS than girls without overweight or overweight at only one age. Height was positively associated with PCOS risk at all ages. Girls who were persistently tall or changed from tall to average height had a higher risk of developing PCOS than girls with average height growth., Conclusion: Overweight and tall stature in childhood are positively associated with PCOS risk, but birthweight is not., (© 2021 The Author(s) Published by S. Karger AG, Basel.)

Aims: We examined whether a woman's birthweight, childhood height, body mass index (BMI), and BMI changes from childhood to pregnancy were associated with risks of gestational diabetes mellitus (GDM)., Methods: We studied 13,031 women from the Copenhagen School Health Records Register born 1959-1996 with birthweight and measured anthropometric information at ages 7 and/or 13. The diagnosis of GDM (n = 255) was obtained from a national health register. Risk ratios (RR) were estimated using log-linear binomial regression., Results: Own birthweight and childhood height were inversely associated with GDM. Girls with overweight at age 7 had a higher risk of GDM than girls with normal-weight (RR: 1.79, 95% CI: 1.31, 2.47). Compared to women with normal-weight in childhood and adulthood, risks of GDM were higher in women who developed overweight from age 7 to pregnancy (RR: 4.62; 3.48, 6.14) or had overweight at both times (RR: 4.71; 3.24, 6.85). In women whose BMI normalized from age 7 to pregnancy the RR for GDM was 1.08 (0.47, 2.46)., Conclusions: Lower birthweight, shorter childhood height, and higher childhood BMI are associated with increased risks of GDM. Efforts to help girls maintain a normal BMI before pregnancy may be warranted to minimize risks of GDM., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Socioeconomic status (SES) is inversely associated with risks of type 2 diabetes (T2D). We investigated if young men's cognitive function, measured by intelligence test scores and educational level, as determinants of SES modified associations between body mass index (BMI) and height with the risk of T2D. 369 989 young men from the Danish Conscription Database born between 1939 and 1959 with information on measured height, weight, intelligence test scores, and education were linked to the Danish National Patient Register. During follow-up from 1977 through 2015, T2D was recorded in 32 188 men. Hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated by Cox regressions. BMIs below-average (z-scores ≤ 0) were not related to risks of T2D. For BMIs above-average (z-scores > 0), positive associations between BMI and T2D were slightly stronger among men with higher intelligence test scores or longer educations than among men with lower levels of these factors (p interaction -values < 0.004). Irrespective of BMI, incidence rates of T2D were higher among men with low levels of intelligence test score and education. Height was inversely associated with T2D (per z-score, HR = 0.96 (95% CI 0.95-0.97) and the association did not vary by intelligence test scores or education (all p interaction -values > 0.59). While below-average BMI was not associated with T2D risk, above-average BMIs were and these association were stronger among men with high cognitive function. Nevertheless, T2D risk was higher at lower levels of cognitive function throughout the range of BMI. Height was inversely associated with T2D and it was not modified by cognitive function.

Background and Aims: Children with a growth trajectory of overweight have higher levels of cardiovascular disease (CVD) risk factors than children with a normal-weight trajectory. However, less is known about how trajectories of body mass index (BMI) across the rest of the BMI spectrum relate to CVD risk factors and whether adult BMI affects these associations. Our aim was to examine associations between childhood BMI trajectories and adult CVD risk factors., Methods: We included 2466 individuals with childhood weights and heights (ages 6-14) from the Copenhagen School Health Records Register and adult CVD risk factors (ages 20-81) from the Copenhagen City Heart Study. Associations between childhood BMI trajectories identified by latent class modelling and CVD risk factors were examined using generalized linear regression analyses with and without adjustment for adult BMI. Normal-weight and overweight were defined by growth references from the Centers for Disease Control and Prevention., Results: We identified four childhood trajectories within the normal-weight spectrum and one trajectory of overweight. Compared to the trajectory with the lowest BMI level, several higher BMI trajectories were associated with worse circumference, HDL and glucose homeostasis in adulthood. The highest trajectory was additionally associated with higher total cholesterol and triglycerides. When adjusting for adult BMI, the higher BMI trajectories had lower waist circumference, blood pressure and triglycerides., Conclusions: Trajectories of BMI within the normal-weight range and in the overweight range are associated with a worse CVD risk profile than in the lowest BMI trajectory, and these associations are modifiable by growth after childhood., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Maternal overweight (including obesity) is an established risk factor for gestational hypertension and pre-eclampsia. However, it is largely unknown whether body size before adulthood relates to these diseases., Objectives: We examined whether childhood BMI (in kg/m2) and changes in BMI from childhood to adulthood were associated with gestational hypertension and pre-eclampsia., Methods: Using the Copenhagen School Health Records Register, we studied 49,600 women born between 1940 and 1996 with height and weight measurements at 7 y and/or 13 y who had their first singleton birth between ages 18 and 45 y. Women with gestational hypertension (n = 496) and pre-eclampsia (n = 1804) were identified from the International Classification of Disease codes in the Danish National Patient Register. Adult overweight (including obesity) was defined as a BMI ≥25. We used log-linear binomial regression to estimate risk ratios (RRs) and 95% CIs., Results: At 13 y, as BMI increased above average (z score >0, or the 42nd percentile of the CDC BMI reference), RR for gestational hypertension was 1.66 (95% CI: 1.42, 1.94) and that for pre-eclampsia was 1.57 (95% CI: 1.46, 1.70) per BMI z score. In a subset of 13,160 women, development of overweight from childhood to adulthood and having overweight at both ages were associated with higher risks of the outcomes than in those with a normal BMI at both ages. No increased risks were observed in women whose BMI normalized from childhood to adulthood: RR was 2.04 (95% CI: 0.93, 4.47) for gestational hypertension and 1.11 (95% CI: 0.63, 1.93) for pre-eclampsia., Conclusions: Above-average childhood BMI values and development of overweight from childhood to adulthood were associated with increased risks of gestational hypertension and pre-eclampsia, whereas normalizing BMI from childhood to conception attenuated the risks. Thus, interventions aiming at normalizing BMI in girls with high values may be warranted to help prevent these obstetric diseases., (Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.)

Background: Most identified risk factors for cancer primarily occur in adulthood. As cancers generally have long latency periods, it is possible that risk factors acting earlier in life and accumulation of risks across the life course are important. Thus, focusing only on adult overweight as a modifiable risk factor may overlook childhood as an important aetiologic time window when body size is relevant for future cancer risks. The objective of this study was to review the evidence for associations between birthweight, body mass index (BMI), height and growth from 7-13 years and adult cancer risks based on studies using the Copenhagen School Health Records Register., Methods: The register contains measured anthropometric information on 372,636 children born in 1930-1989. All studies examining associations between early life body size and risks of adult cancer (until 85 years, diagnosed in 1968-2015) were included, comprising 31 studies on 16 different cancer sites. Cancer diagnoses were retrieved via individual-level linkages to the Danish Cancer Registry., Results: Birthweight was differentially associated with bladder, breast, colon, glioma, Hodgkin's disease, liver, kidney (renal cell), melanoma, ovarian, rectal, testicular and thyroid cancer. BMI in childhood was positively associated with risks of bladder (only late childhood), colon, endometrial, kidney, liver, oesophageal (only late childhood), ovarian, pancreatic (<70 years), prostate (only before childhood height adjustment) and thyroid cancer, whereas it was inversely associated with breast cancer. Child height was positively associated with breast, colon, endometrial, glioma, Hodgkin's disease, kidney, melanoma, oesophageal (only women), ovarian, prostate, testicular and thyroid cancer and inversely associated with bladder cancer. Greater than average increases in childhood BMI or linear growth at ages 7-13 increased risks of several cancers., Conclusions: Early life body size and growth are associated with many, but not all adult cancers, suggesting that the aetiology of several cancers may lie earlier in life than previously thought.

Objective: We investigated the association between changes in weight status from childhood through adulthood and subsequent type 2 diabetes risks and whether educational attainment, smoking, and leisure time physical activity (LTPA) modify this association., Research Design and Methods: Using data from 10 Danish and Finnish cohorts including 25,283 individuals, childhood BMI at 7 and 12 years was categorized as normal or high using age- and sex-specific cutoffs (<85th or ≥85th percentile). Adult BMI (20-71 years) was categorized as nonobese or obese (<30.0 or ≥30.0 kg/m 2 , respectively). Associations between BMI patterns and type 2 diabetes (989 women and 1,370 men) were analyzed using Cox proportional hazards regressions and meta-analysis techniques., Results: Compared with individuals with a normal BMI at 7 years and without adult obesity, those with a high BMI at 7 years and adult obesity had higher type 2 diabetes risks (hazard ratio [HR] girls 5.04 [95% CI 3.92-6.48]; HR boys 3.78 [95% CI 2.68-5.33]). Individuals with a high BMI at 7 years but without adult obesity did not have a higher risk (HR girls 0.74 [95% CI 0.52-1.06]; HR boys 0.93 [95% CI 0.65-1.33]). Education, smoking, and LTPA were associated with diabetes risks but did not modify or confound the associations with BMI changes. Results for 12 years of age were similar., Conclusions: A high BMI in childhood was associated with higher type 2 diabetes risks only if individuals also had obesity in adulthood. These associations were not influenced by educational and lifestyle factors, indicating that BMI is similarly related to the risk across all levels of these factors., (© 2020 by the American Diabetes Association.)

Childhood obesity adversely affects the structure and function of the cardiovascular system, but the relationship between excessive weight gain during childhood and adult cardiovascular disease (CVD) is not fully understood. This review summarizes evidence for associations of change in body mass index (BMI) from childhood onwards with CVD outcomes. We found that excessive gain in BMI from childhood onwards was consistently associated with the presence of CVD risk factors, with increased risks of coronary heart disease, and there were suggestions of associations with stroke, atrial fibrillation and heart failure, but a lack of evidence precludes firm conclusions. These results indicate that the risk of CVD can be traced back to child ages and highlights the importance of primordial prevention of CVD by preventing excessive weight gain in childhood., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Observed associations between breastfeeding and reduced risk of type 2 diabetes in adulthood may be confounded. We examined if the duration of breastfeeding in infancy was associated with the risk of type 2 diabetes in adulthood after adjustment for a range of prenatal and postnatal risk factors. We prospectively followed 6,044 individuals from the Copenhagen Perinatal Cohort born 1959-1961. Duration of any breastfeeding (≤0.5, >0.5-1, >1-2, >2-4, >4 months) was assessed at the infant's 1-year health examination. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for type 2 diabetes (at age ≥30 years, 237 persons) by breastfeeding duration without and with adjustment for parental social status and education, maternal pre-pregnancy body mass index (BMI), maternal diabetes and smoking during pregnancy, gestational weight gain, parity, preterm birth, birth weight, sex, and BMI at ages 7 and 41-43 years. In the unadjusted analysis, compared with infants breastfed for ≤0.5 month, those breastfed for >4 months had a 51% reduced risk of type 2 diabetes (HR = 0.49; 95% CI [0.32, 0.75]). After the stepwise adjustment for putative early life confounders, this was attenuated to a nonsignificant 31% reduced risk (HR = 0.69; 95% CI [0.44, 1.07]). Adjustment for childhood and adulthood BMI minimally changed the results. We found that the inverse association between the duration of breastfeeding and risk of type 2 diabetes in adulthood is considerably weakened and no longer significant after adjustment for prenatal and postnatal factors in the infant and mother., (© 2019 John Wiley & Sons Ltd.)

Background: Although short adult height is generally associated with increased risks of type 2 diabetes mellitus (T2DM), there are large inconsistencies across studies. The aims of this study were to describe and quantify currently available evidence on the association between adult height and T2DM, to examine whether the reported associations differ by sex, and to examine the shapes of the height and T2DM associations., Methods: Relevant literature was identified using PubMed (1966-May 2018), EMBASE (1947-May 2018) and Google Scholar (May 2018). We identified cross-sectional and cohort studies with original publications on human subjects, which were included in a random-effects meta-analysis., Results: From 15 971 identified sources, 25 studies met the inclusion criteria for the systematic review (N=401 562 individuals). From these 25 studies, 16 (9 cross-sectional studies and 7 cohort studies) were included in the meta-analysis (n=261 496 individuals). The overall random-effects meta-analysis indicated an inverse association between adult height and T2DM (effect estimate=0.88, 95% CI 0.81 to 0.95). No sex differences in the associations between adult height and T2DM were found (effect estimate for men: 0.86, 95% CI 0.75 to 0.99; effect estimate for women: 0.90; 95% CI 0.80 to 1.01; p value for sex interaction=0.80). Due to lack of data, results on the shape of the association between height and T2DM were inconclusive., Conclusions: Shorter height is associated with an increased risk of T2DM and the association does not significantly differ by sex. The currently available data are insufficient to support conclusions regarding the shape of the association between height and T2DM., Trial Registration Number: CRD42017062446., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Children with obesity have a cardiometabolic risk profile that may predispose them to cardiovascular diseases. We examined the associations of childhood body mass index (BMI) and changes in BMI with the risk of atrial fibrillation and flutter (AFF) in adulthood. We conducted a population-based cohort study of Danish schoolchildren aged 7-13 years born from 1930 to 1989. Among 314,140 children, 17,594 were diagnosed with AFF as adults (1977-2014). In both men and women, above-average BMIs in childhood were associated with increased risks of AFF. Children who were persistently heavy at ages 7 and 13 years and children whose BMIs increased from the internal 25.0th-75.0th percentiles or from the internal 75.1th-90.0th percentiles between ages 7 and 13 years had higher risks of AFF in adulthood than children whose BMIs remained in the internal 25.0th-75.0th percentiles at both ages. A decrease in BMI percentile categories between 7 and 13 years of age reduced risks of AFF in adulthood, with risks of AFF reverting to levels similar to those in the reference group for women but not for men. In conclusion, risks of AFF in adulthood increased with higher childhood BMIs. Remission from overweight by age 13 years reduced AFF risks, especially in women., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Although weight gain in mid- to late adult life is associated with an increased risk of colon cancer, it is unclear if increases or losses in weight from childhood to early adulthood are differentially associated with risks of adult colon cancer., Methods: Weight and height were measured at 7 or 13 years and in early adulthood (17-26 years) in 64,675 boys in the Copenhagen School Health Records Register and the Danish Conscription Database. Cases of colon cancer (n = 751) were identified in the Danish Cancer Registry. Boys and young men were categorized as normal weight or overweight. Associations between changes in weight and colon cancer were examined using Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs)., Results: Compared with men with a normal weight at 7 years and in early adulthood, men with overweight at both ages had an increased risk of adult colon cancer (HR: 2.73, 95% CI 1.80-4.15). In contrast, men with overweight at 7 years, but not in early adulthood did not have an increased risk of colon cancer (HR: 0.73, 95% CI 0.35-1.54), nor did men with a normal weight at 7 years and overweight in early adulthood (HR: 1.28, 95% CI 0.96-1.70). Similar results were observed for weight status at age 13 years combined with early adulthood., Conclusions: Childhood overweight that persists into early adulthood is associated with an increased risk of colon cancer, whereas overweight that disappears before early adulthood or developed after childhood is not.

We conducted a systematic review and meta-analysis of observational studies investigating the association between antibiotic exposure in infancy and risk of childhood overweight and obesity. Thirteen studies, including a total of 527 504 children, were included in the systematic review and 8 were included in meta-analyses. Exposure to antibiotics in infancy was associated with an increased odds ratio (OR) of childhood overweight and obesity (OR 1.11, 95% confidence interval [CI] 1.02-1.20). Whereas exposure to 1 treatment only and exposure between 6 and 24 months were not associated with increased risk of childhood overweight and obesity, exposure to >1 treatment was associated with an OR of 1.24 (95% CI 1.09-1.43) and exposure within the first 6 months of life was associated with an OR of 1.20 (95% CI 1.04-1.37). In conclusion, antibiotic exposure in infancy was associated with a slightly increased risk of childhood overweight and obesity, mainly if children were exposed to repeated treatments or treatment within the first 6 months of life. It is unclear whether this association is mediated via direct effects of antibiotics on the gut microbiota., (© 2018 John Wiley & Sons Ltd.)

Background: Childhood overweight is associated with an increased risk of type 2 diabetes in adulthood. We investigated whether remission of overweight before early adulthood reduces this risk., Methods: We conducted a study involving 62,565 Danish men whose weights and heights had been measured at 7 and 13 years of age and in early adulthood (17 to 26 years of age). Overweight was defined in accordance with Centers for Disease Control and Prevention criteria. Data on type 2 diabetes status (at age ≥30 years, 6710 persons) were obtained from a national health registry., Results: Overweight at 7 years of age (3373 of 62,565 men; 5.4%), 13 years of age (3418 of 62,565; 5.5%), or early adulthood (5108 of 62,565; 8.2%) was positively associated with the risk of type 2 diabetes; associations were stronger at older ages at overweight and at younger ages at diagnosis of type 2 diabetes. Men who had had remission of overweight before the age of 13 years had a risk of having type 2 diabetes diagnosed at 30 to 60 years of age that was similar to that among men who had never been overweight (hazard ratio, 0.96; 95% confidence interval [CI], 0.75 to 1.21). As compared with men who had never been overweight, men who had been overweight at 7 and 13 years of age but not during early adulthood had a higher risk of type 2 diabetes (hazard ratio, 1.47; 95% CI, 1.10 to 1.98), but their risk was lower than that among men with persistent overweight (hazard ratio [persistently overweight vs. never overweight], 4.14; 95% CI, 3.57 to 4.79). An increase in body-mass index between 7 years of age and early adulthood was associated with an increased risk of type 2 diabetes, even among men whose weight had been normal at 7 years of age., Conclusions: Childhood overweight at 7 years of age was associated with increased risks of adult type 2 diabetes only if it continued until puberty or later ages. (Funded by the European Union.).

Background: Short adults have an increased risk of type 2 diabetes. Although adult height results from childhood growth, the effects of height and growth trajectories during childhood are sparsely investigated. We investigated sex-specific associations between childhood height, growth and adult type 2 diabetes, including potential influences of birthweight and childhood body mass index (BMI)., Methods: We followed 292 827 individuals, born 1930-83, from the Copenhagen School Health Records Register in national registers for type 2 diabetes (11 548 men; 7472 women). Weights and heights were measured at ages 7-13 years. Hazard ratios (HR) of type 2 diabetes (age ≥30 years) were estimated without and with adjustment for birthweight and BMI., Results: In men, associations between height and type 2 diabetes changed from inverse for below-average heights at age 7 years to positive for above-average heights at 13 years. No consistent associations were observed among women. These associations were not affected by birthweight. After adjustment for BMI, below-average childhood heights were inversely associated with type 2 diabetes among men (HR range: 0.91-0.93 per z-score) but above-average heights were not. Among women, after adjustment for BMI, below- and above-average heights in childhood were inversely associated with type 2 diabetes (HR range: 0.91-0.95). Greater height growth from 7 to 13 years was positively associated with type 2 diabetes in men and women., Conclusions: After adjustment for BMI, short childhood height at all ages and greater growth during childhood are associated with an increased risk of type 2 diabetes, suggesting that this period of life warrants mechanistic investigations., (© 2017 John Wiley & Sons Ltd.)

Objective: This study investigated how a wide spectrum of body mass index (BMI) values at ages 7 to 13 years are associated with type 2 diabetes throughout adulthood, including potential modifying effects of sex and birth weight., Methods: From the Copenhagen School Health Records Register, 292,827 individuals, born between 1930 and 1989, were followed in national registers for type 2 diabetes (women, n = 7,472; men, n = 11,548). Heights and weights were measured at ages 7 to 13 years., Results: Below-average BMIs, with few exceptions, were not associated with type 2 diabetes. Above-average BMIs had positive associations that were stronger in women than men, stronger in younger birth cohorts, and weaker with older age at diagnosis. Women born 1930-1947, 1948-1965, and 1966-1983 with above-average BMIs at 13 years (≥18.2 kg/m 2 ) had hazard ratios (95% confidence intervals) ranging from 2.12 (1.91-2.36) to 2.84 (2.31-3.49) per z score when diagnosed at 30 to 47 years. Birth weight did not modify these associations., Conclusions: Childhood BMIs below average are not associated with type 2 diabetes, whereas childhood BMIs above average are strongly associated with type 2 diabetes in adulthood, corresponding to excess risks even at levels below international definitions of overweight. The associations are stronger in women than men but are not affected by birth weight., (© 2017 The Obesity Society.)

Background: Heavy children have an increased risk of being overweight young adults. Whether this risk remains in late adulthood is not well-understood. We investigated body mass index (BMI; kg m(-2)) tracking from childhood to late adulthood., Methods: From the Copenhagen School Health Records Register, 72 959 men and 25 252 women born between 1930 and 1989 with BMI values at 7 and/or 13 years and as adults were included. Using a meta-regression approach, age- and sex-specific partial correlation analyses and logistic regressions were performed., Results: Correlations between BMI at 7 years and young adult ages (18-19 years) were r=0.55 for men and r=0.55 for women. At late ages (60-69 years) these were r=0.28 for men and r=0.26 for women. The correlations did not differ by birth years. Compared with normal-weight 7-year-olds, overweight children had a higher odds of overweight at 18-19 years; odds ratio (OR)=14.02 (95% confidence interval (CI): 12.14-16.19) for men and 10.46 (95% CI: 4.82-22.70) for women. At ages 60-69 years ORs were 5.46 (95% CI: 0.95-31.36) for men and 1.61 (95% CI: 0.83-3.15) for women. Correlations and ORs were stronger at age 13 years than age 7 years as expected, but the overall patterns were similar., Conclusions: BMI tracking was weaker at late adult ages than at young adult ages. Although BMI tracks across the life course, childhood BMI is relatively poor at identifying later adult overweight or obesity at ages when chronic diseases generally emerge.

Purpose: We previously showed that childhood height is positively associated with prostate cancer risk. It is, however, unknown whether childhood height exerts its effects independently of or through adult height. We investigated whether and to what extent childhood height has a direct effect on the risk of prostate cancer apart from adult height., Methods: We included 5,871 men with height measured at ages 7 and 13 years in the Copenhagen School Health Records Register who also had adult (50-65 years) height measured in the Danish Diet, Cancer and Health study. Prostate cancer status was obtained through linkage to the Danish Cancer Registry. Direct and total effects of childhood height on prostate cancer risk were estimated from Cox regressions., Results: From 1996 to 2012, 429 prostate cancers occurred. Child and adult heights were positively and significantly associated with prostate cancer risk. When adjusted for adult height, height at age 7 years was no longer significantly associated with the risk of prostate cancer. Height at 13 years was significantly and positively associated with prostate cancer risk even when adult height was adjusted for; per height z-score the hazard ratio was 1.15 [95% confidence interval (CI) 1.01-1.32]., Conclusions: The effect of height at 13 years on the risk of prostate cancer was not entirely mediated through adult height, suggesting that child height and adult height may be associated with prostate cancer through different pathways.

Background: Weight and weight gain throughout infancy are related to later obesity, but whether the strength of the associations varies during the infancy period is uncertain., Aims: Our aims were to identify the period of infancy when change in body weight has the strongest association with adult body mass index (BMI) and also the extent to which these associations during infancy are mediated through childhood BMI., Methods: The Copenhagen Perinatal Cohort, in which participants were followed from birth through 42 years of age, provided information on weight at 12 months and BMI at 42 years for 1633 individuals. Information on weight at birth, 2 weeks, 1, 2, 3, 4 and 6 months was retrieved from health visitors' records and information on BMI at ages 7 and 13 years from school health records. The associations of infant weight and weight gain standard deviation scores (SDS) with adult BMI-SDS were analyzed using multiple linear regression and path analysis., Results: Higher-weight-SDS at all ages from birth to an age 12 months were associated with higher-BMI-SDS at 42 years (regression coefficients 0.08-0.12). Infant weight gain-SDS was associated with greater BMI-SDS at 42 years only between birth and 3 months (0.09, 95% confidence intervals (CI) 0.04, 0.15) driven by an association between 2 and 3 months (0.12, 95% CI: 0.04, 0.20). The latter was partly mediated through later BMI in the path analysis. Infant weight gain-SDS between 3 and 12 months was not associated with greater BMI-SDS at 42 years., Conclusions: Faster weight gain during only the first 3 months of infancy was associated with increased adult BMI, although not in a consistent monthly pattern. Adult BMI is more sensitive to high weight gain during early infancy than late infancy, but not specifically to the first month of life.