Daily physical activity patterns from hip- and wrist-worn accelerometers.

Accelerometer wear location may influence physical activity estimates. This study investigates this relationship through the examination of activity patterns throughout the day. Participants from the aging research evaluating accelerometry (AREA) study (n men = 37, n women = 47, mean age (SD) = 78.9 (5.5) years) were asked to wear accelerometers in a free-living environment for 7 d at three different wear locations; one on each wrist and one on the right hip. During waking hours, wrist-worn accelerometers consistently produced higher median activity counts, about 5 × higher, as well as wider variability compared to hip-worn monitors. However, the shape of the accrual pattern curve over the course of the day for the hip and wrist are similar; there is a spike in activity in the morning, with a prolonged tapering of activity level as the day progresses. The similar patterns of hip and wrist activity accrual provide support that each location is capable of estimating total physical activity volume. The examination of activity patterns over time may provide a more detailed way to examine differences in wear location and different subpopulations.

Height and the risk of gestational diabetes: variations by race/ethnicity.

AIMS: Gestational diabetes is a common pregnancy complication affecting races/ethnicities disproportionally. Adult height, an indicator of both genetic and early-life factors, is inconsistently associated with gestational diabetes risk. We examined the association and whether it varies by races in a nationally representative US cohort. METHODS: Analyses were conducted among 135 861 pregnancies in the Consortium on Safe Labor, 5567 of which were diagnosed with gestational diabetes based on medical records review. Generalized estimating equations were used to estimate odds ratios (95% confidence intervals) of gestational diabetes, controlling for other risk factors including body weight. Additionally, a meta-analysis of 15 761 pregnancies with gestational diabetes and 205 828 without gestational diabetes was conducted to estimate the pooled mean difference in height between those with gestational diabetes and control subjects. RESULTS: Height was inversely associated with gestational diabetes risk across races/ethnicities, with the strongest association among Asians (P for interaction < 0.01). Comparing extreme quartiles (> 168 vs. < 157 cm), adjusted odds ratios (95% confidence intervals) were 0.18 (0.09-0.36) for Asians/Pacific Islanders, 0.33 (0.29-0.38) for non-Hispanic white women, 0.39 (0.31-0.51) for Hispanics and 0.59 (0.47-0.75) for non-Hispanic black women. Meta-analysis found women with gestational diabetes to be significantly shorter than others. CONCLUSIONS: Taller women are at lower risk of developing gestational diabetes, with the magnitude of association varying significantly across races/ethnicities.

Physical activity and weight gain prevention in older men.

BACKGROUND: Physical activity and adiposity are important predictors of mortality, even in older individuals. However, it is unclear how much physical activity is needed to prevent weight gain in older persons. PURPOSE: To examine the associations of different amounts of physical activity with weight gain prevention in older men. METHODS: A total of 5973 healthy men (mean age, 65.0 years) from the Harvard Alumni Health Study were followed from 1988 to 1998. At baseline (1988), in 1993 and 1998, men reported their recreational physical activity and body weight. Physical activity was categorized as: <7.5 metabolic equivalent (MET)-h per week (7.5 MET-h per week corresponds to the minimum required by the 2008 US federal guidelines), 7.5 to <21 MET-h per week (21 MET-h per week corresponds to the 2002 Institute of Medicine (IOM) guideline) and 21 MET-h per week. Meaningful weight gain was defined as an increase of ≥3% of body weight. RESULTS: Overall, weight tended to be stable over any 5-year period; mean change, -0.08 (s.d.=4.44) kg. However, ∼21% of men experienced meaningful weight gain over any 5-year period. In multivariate analyses, compared with men expending ≥ 21 MET-h per week, those expending 7.5 to <21 MET-h per week had an odds ratio (OR) of 1.35 (95% confidence interval: 1.03, 1.77) for meaningful weight gain, and men expending <7.5 MET-h per week, an OR of 1.16 (1.01, 1.33; P trend=0.09). CONCLUSIONS: Among older men, those with lesser levels of physical activity were more likely to gain weight than men satisfying the 2002 IOM guidelines of ≥21 MET-h per week (∼60 min day(-1) of moderate-intensity physical activity).