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Physical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass. The precise dose that benefits bone remains unclear as methods commonly used to analyze PA data are unsuitable for measuring bone‐relevant PA. Using improved accelerometry methods, this study identified the amount and intensity of PA most strongly associated with bone outcomes in 11–12‐year‐olds. Participants (n = 770; 382 boys) underwent tibial peripheral quantitative computed tomography to assess trabecular and cortical density, endosteal and periosteal circumference and polar stress‐strain index. Seven‐day wrist‐worn raw acceleration data averaged over 1‐s epochs was used to estimate time accumulated above incremental PA intensities (50 milli‐gravitational unit (mg) increments from 200 to 3000 mg). Associations between time spent above each 50 mg increment and bone outcomes were assessed using multiple linear regression, adjusted for age, sex, height, weight, maturity, socioeconomic position, muscle cross‐sectional area and PA below the intensity of interest. There was a gradual increase in mean R2 change across all bone‐related outcomes as the intensity increased in 50 mg increments from >200 to >700 mg. All outcomes became significant at >700 mg (R2 change = 0.6%–1.3% and p = 0.001–0.02). Any further increases in intensity led to a reduction in mean R2 change and associations became non‐significant for all outcomes >1500 mg. Using more appropriate accelerometry methods (1‐s epochs; no a priori application of traditional cut‐points) enabled us to identify that ∼10 min/day of PA >700 mg (equivalent to running ∼10 km/h) was positively associated with pQCT‐derived measures of bone density, geometry and strength in 11–12‐year‐olds. Highlights: Accelerometry methods that are commonly used to assess free‐living, bone‐relevant physical activity (PA) are not well suited to measuring bone‐specific characteristics of PA (short bursts of high‐impact activity).Processing raw acceleration data using much shorter epochs (1‐s) and using incremental 50 mg intensity thresholds (rather than traditional, broad intensity thresholds) enabled a bone‐specific, beneficial intensity to be identified.The methods outlined provide a means for more precisely assessing free‐living bone‐relevant PA and permit the transparent and reproducible analysis of raw accelerometry data, which will enhance our ability to quantify dose‐response associations in the future. [ABSTRACT FROM AUTHOR]

While physical activity (PA) is understood to promote vascular health, little is known about whether the daily and weekly patterns of PA accumulation associate with vascular health. Accelerometer‐derived (activPAL3) 6‐ or 7‐day stepping was analyzed for 6430 participants in The Maastricht Study (50.4% women; 22.4% Type 2 diabetes mellitus (T2DM)). Multivariable regression models examined associations between stepping metrics (average step count, and time spent slower and faster paced stepping) with arterial stiffness (measured as carotid–femoral pulse wave velocity (cfPWV)), and several indices of microvascular health (heat‐induced skin hyperemia, retinal vessel reactivity and diameter), adjusting for confounders and moderators. PA pattern metrics were added to the regression models to identify associations with vascular health beyond that of stepping metrics. Analyses were stratified by T2DM status if an interaction effect was present. Average step count and time spent faster paced stepping was associated with better vascular health, and the association was stronger in those with compared to those without T2DM. In fully adjusted models a higher step count inter‐daily stability was associated with a higher (worse) cfPWV in those without T2DM (std β = 0.04, p = 0.007) and retinal venular diameter in the whole cohort (std β = 0.07, p = 0.002). A higher within‐day variability in faster paced stepping was associated with a lower (worse) heat‐induced skin hyperemia in those with T2DM (std β = −0.31, p = 0.008). Above and beyond PA volume, the daily and weekly patterns in which PA was accumulated were additionally associated with improved macro‐ and microvascular health, which may have implications for the prevention of vascular disease. [ABSTRACT FROM AUTHOR]

The role of variation of glucokinase (GCK) in the determination of fasting glucose and birth weight is examined using a tagging single-nucleotide polymorphism (tSNP) approach. A comprehensive analysis of common variation of the glucokinase gene has indicated that this is the first gene to be reproducibly associated with fasting glucose and fetal growth.

OBJECTIVE. The aim of this study was to evaluate whether adaptive responses made to the uterine or very early infant environment are affecting the current metabolic health of young children in the United Kingdom. METHODS. Participants were 300 healthy children and their parents from the EarlyBird Diabetes Study cohort. Children were recruited from randomly selected schools at 5 years of age. Retrospective measures were maternal prepregnancy weight (n = 230), maternal fasting glucose levels at 28 weeks of pregnancy (n = 27), birth weight, and infant weight at ages 3 and 6 weeks. Prospective measures were insulin resistance, height, weight, and percentage of body fat (sum of 5 skinfold measurements) at ages 5, 6, 7, and 8 years. RESULTS. Maternal third-trimester fasting glucose levels were associated positively with birth weight but were not associated with either weight or insulin resistance for the same children at 8 years. Birth weight was unrelated to insulin resistance at 8 years. There were no relationships between weight change in the first weeks of life and weight, percentage of fat, or insulin resistance at 8 years. Longer breastfeeding correlated inversely, although weakly, with percentage of body fat for boys only. Current weight was correlated with insulin resistance at 8 years. CONCLUSIONS. For these contemporary children, neither the gestational environment nor early postnatal growth predicted insulin resistance, which was best predicted by current weight. There was no evidence that predictive adaptive responses made by the fetus or infant affected the child's weight or insulin resistance later in childhood. Key Words birth weight, body composition, body mass index, breasffeeding, children, fetal programming, insulin resistance, metabolic syndrome, obesity, weight Abbreviation HOMA-IR--homeostasis model assessment-insulin resistance, GENETIC SUSCEPTIBILITY TO the metabolic syndrome can have changed little in recent decades, but environmental risk has increased dramatically. The industrialized world is experiencing an epidemic of childhood and adult [...]

Objective. Recent studies of type 2 diabetes in young populations consistently show a predominance of affected girls over boys. Girls are more insulin resistant than boys. We aimed in the present report to establish how much of the sex difference in insulin resistance is intrinsic. Methods. EarlyBird is a community-based, nonintervention cohort study of 307 healthy children from school entry at age 5 years. It asks the question: which children are insulin resistant and why? Anthropometric measures, physical activity, resting energy expenditure, and insulin resistance and its metabolic correlates were measured. Results. At 5 years, insulin resistance was 35% higher in girls than in boys. Girls carried 26% more subcutaneous fat despite similar body weights. However, after correcting for anthropometric variables and physical activity, girls remained 33% more insulin resistant than boys. Triglycerides were significantly higher in girls, and high-density lipoprotein cholesterol and sex hormone--binding globulin were significantly lower. Conclusions. Sex-linked genes may account for the intrinsic sex difference observed. These genes may have an important impact on the development of insulin resistance and the metabolic syndrome and may help b explain the female preponderance of type 2 diabetes in children. Their identification may also help in understanding the pathogenesis of insulin resistance. Pediatrics 2004;113:82-86; type 2 diabetes, insulin resistance, sex difference, programming, sex-linked genes., Type 2 diabetes is becoming a global public health problem. (1) The World Health Organization predicts a rise in prevalence of type 2 diabetes during the 30 years 1995-2025 of [...]