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Background:Sleep disturbance, a correlate of which is daytime napping, has been hypothesised to be associated with risk of breast and other cancers.Methods:We estimated relative risks (RR) of breast and other invasive cancers by the reported frequency of daytime napping in a large prospective cohort of middle-aged women in the UK.Results:During an average of 7.4 years of follow-up, 20 058 breast cancers and 31 856 other cancers were diagnosed. Over the first 4 years of follow-up, daytime napping (sometimes/usually vs rarely/never) was associated with slightly increased risks of breast cancer (RR=1.10, 95% CI 1.06-1.15) and of other cancers (RR=1.12, 1.08-1.15), but the RRs decreased significantly with increasing follow-up time (P=0.001 and P=0.01, respectively, for trend). Four or more years after baseline, there was no elevated risk of breast cancer (RR=1.00, 0.96-1.05), and only marginally greater risk of other cancers (RR=1.04, 1.01-1.07).Conclusion:The effect of pre-clinical disease is a likely explanation for the short-term increased risk of breast and other cancers associated with daytime napping. [ABSTRACT FROM AUTHOR]

Background:Greater adiposity in early life has been linked to increased endometrial cancer risk in later life, but the extent to which this association is mediated through adiposity in later life is unclear.Methods:Among postmenopausal women who had never used menopausal hormone therapies and reported not having had a hysterectomy, adjusted relative risks (RRs) of endometrial cancer were estimated using Cox regression.Results:Among 249 791 postmenopausal women with 7.3 years of follow-up on average (1.8 million person-years), endometrial cancer risk (n=1410 cases) was strongly associated with current body mass index (BMI) at baseline (RR=1.87 per 5 kg m−2 increase in BMI, 95% confidence interval (CI): 1.77-1.96). Compared with women thinner than average at age 10, the increased risk among women plumper at age 10 (RR=1.27, 95% CI: 1.09-1.49) disappeared after adjustment for current BMI (RR=0.90, 95% CI: 0.77-1.06). Similarly, compared with women with clothes size 12 or less at age 20, the increased risk among women with clothes size 16 or larger (RR=1.87, 95% CI: 1.61-2.18) was not significant after adjustment for current BMI (RR=1.03, 95% CI: 0.88-1.22).Conclusion:Among women who have never used hormone therapy for menopause, the association between body size in early life and endometrial cancer risk in postmenopausal women can be largely explained by women's current BMI. [ABSTRACT FROM AUTHOR]

Background/Objectives:Vitamin C intake has been inversely associated with breast cancer risk in case-control studies, but not in meta-analyses of cohort studies using Food Frequency Questionnaires, which can over-report fruit and vegetable intake, the main source of vitamin C. This is the first study to investigate associations between vitamin C intake and breast cancer risk using food diaries.Subjects/Methods:Estimated dietary vitamin C intake was derived from 4-7 day food diaries pooled from five prospective studies in the UK Dietary Cohort Consortium. This nested case-control study of 707 incident breast cancer cases and 2144 matched controls examined breast cancer risk in relation to dietary vitamin C intake using conditional logistic regression adjusting for relevant covariates. Additionally, total vitamin C intake from supplements and diet was analysed in three cohorts.Results:No evidence of associations was observed between breast cancer risk and vitamin C intake analysed for dietary vitamin C intake (odds ratios (OR)=0.98 per 60 mg/day, 95% confidence interval (CI): 0.88-1.09, P trend=0.7), dietary vitamin C density (OR=0.97 per 60 mg/day, 95% CI: 0.87-1.07, P trend=0.5 ) or total vitamin C intake (OR=1.01 per 60 mg/day, 95% CI: 0.99-1.03, P trend=0.3). Additionally, there was no significant association for post-menopausal women (OR=1.02 per 60 mg/day, 95% CI: 0.99-1.05, P trend=0.3).Conclusions:This pooled analysis of individual UK women found no evidence of significant associations between breast cancer incidence and dietary or total vitamin C intake derived uniquely from detailed diary recordings. [ABSTRACT FROM AUTHOR]

This longitudinal study examined behavioral, cognitive, and demographic factors associated with early school dropout. Follow-up assessments were completed on a sample of girls (n = 248) and boys (n = 227) who had first been seen when they were in the seventh grade. School status was determined for all living subjects; 99% of them were interviewed individually in the fifth annual test wave. Overall, 14% of the group had dropped out of school prior to completing grade 11. The clusters of males and females most vulnerable to early school dropout were characterized in grade 7 by high levels of aggressiveness and low levels of academic performance (82% early dropout in males; 47% early dropout in females). In seventh grade, subjects who subsequently dropped out tended to affiliate with persons who were also at risk for dropout. Socioeconomic status, race, and early parenthood were also associated with school dropout. The primary outcomes were supported by convergent variable-oriented and person-oriented analyses. Some developmental dynamics of the phenomena are discussed. [ABSTRACT FROM AUTHOR]

Objective Adult obesity is associated with a variety of acute and chronic illnesses. Although high birthweight is known to predict obesity in middle age, the relationship between low birthweight and obesity is less clear. This study examines the association between birthweight and obesity in middle-aged women, and investigates whether the association is modified by other factors. Methods The Million Women Study is a large population-based prospective cohort study of middle-aged UK women. This analysis is based on 372 542 women who reported their birthweight, current body size, and other information in a follow-up survey administered approximately 3 years after recruitment (mean age 58 years at follow-up). Logistic regression was used to estimate relative risk for being obese in adulthood (body mass index>30 kg/m) by birthweight, both unadjusted and adjusted for reported adult height, parental heights, and a range of social and lifestyle factors, including socio-economic status, parental smoking at birth, being breast fed, reproductive history and health behaviours. Results There was a U-shaped relationship between birthweight and adult obesity. Compared to women of intermediate birthweight (3.0–3.5 kg), the relative risk of being obese was 1.26 (95% CI 1.23 to 1.29) for women with low birthweight (<2.5 kg), and 1.33 (1.30 to 1.37) for women with high birthweight (>4.0 kg). After adjustment for height, the relative risk of being obese associated with low birthweight was attenuated (from 1.26 to 1.15), while the relative risk associated with high birthweight was increased (from 1.33 to 1.44). Other health and lifestyle characteristics did not substantially change the obesity-related relative risks at different birthweight. Conclusion Birthweight has a U-shaped relationship with obesity in middle age. This relationship tends towards being J-shaped after adjustment for adult height. [ABSTRACT FROM PUBLISHER]

Objective To compare the relationship between body mass index (BMI) and physical activity for the risk of ankle, wrist and hip fractures in a large prospective study of postmenopausal women in the UK. Methods In 1996–2001, women recruited into the Million Women Study completed a self-administered questionnaire asking about body size, physical activity, disease history, and lifestyle and reproductive factors. Incident ankle, wrist and hip fractures were identified through self-report in a follow-up questionnaire completed an average of 3.2 years after recruitment. RRs and CIs for each fracture site in postmenopausal women by BMI and physical activity at recruitment were calculated using Cox regression models, adjusted for socio-economic status, smoking and other health and lifestyle factors. Results Among 599 550 postmenopausal women, 5114 reported an ankle fracture, 8565 reported a wrist fracture, and 754 reported a hip fracture during follow-up. When compared to lean women (BMI<22.5 kg/m), obese women (BMI≥30 kg/m) had an increased risk of ankle fracture (RR 2.47; 95% CI 2.32 to to 2.63), but a decreased risk of wrist fracture (RR 0.68; 95% CI 0.64 to to 0.72) and hip fracture (RR 0.29; 95% CI 0.23 to to 0.37) (χ<0.001 for the effect of BMI for each fracture site). Physical activity had little influence on the risk of either ankle fracture or wrist fracture, but women who reported strenuous physical activities up to once per week or more often were at a lower risk of hip fracture than women who reported less frequent activity (RR 0.65; 95% CI 0.56 to to 0.76). Conclusions BMI and physical activity have different effects on the incidence of fracture at different sites. While obese women are at increased risk of ankle fracture they are at lower risk of wrist fracture and hip fracture. Physical activity has no marked influence on ankle and wrist fracture but is protective against hip fracture. [ABSTRACT FROM PUBLISHER]

Birth weight and height are correlated and likely to be markers of some aspect of growth that affects cancer risk in adulthood. However, birth weight adds little, if any, additional information to adult height as a predictor of cancer incidence in women.Background Most evidence about associations between birth weight and adult cancer risk comes from studies linking birth records to cancer registration data, where information on known risk factors for cancer is generally lacking. Here, we report on associations between birth weight and cause-specific cancer risk in a large cohort of UK women, and investigate how observed associations are affected by other factors. Methods A total of 453 023 women, born in the 1930s and 1940s, reported their birth weight, maternal smoking, parental heights, age at menarche, adult height, adult smoking, and many other personal characteristics. They were followed for incident cancer. Using Cox regression, relative risks by birth weight were estimated for cancers with more than 1500 incident cases, adjusting for 17 potential confounding factors, individually and simultaneously. Results Birth weight reported in adulthood was strongly correlated with that recorded at birth (correlation coefficient = 0.78, P < 0.0001). Reported birth weight was associated with most of the potential confounding factors examined, the strongest association being with adult height. After 9.2 years follow-up per woman, 39 060 incident cancers were registered (4414 colorectal, 3175 lung, 1795 malignant melanoma, 14 542 breast, 2623 endometrial, 2009 ovarian, 1565 non-Hodgkin lymphoma, and 8937 other cancers). Associations with birth weight were null or weak and reduced after adjustment by adult height (P[trend] > 0.01 for every cancer, after adjustment). In contrast, adult height was strongly related to the risk of every cancer except lung cancer, after adjusting for birth weight and other factors (P[trend] < 0.0001 for most cancers). For lung cancer, adjusting for smoking reduced the association with birth weight. Meta-analyses were dominated by our findings. Conclusion Birth weight and adult height are correlated and likely to be markers of some aspect of growth that affects cancer risk in adulthood. However, birth weight adds little, if any, additional information to adult height as a predictor of cancer incidence in women. [ABSTRACT FROM AUTHOR]