Association of Bone Mineral Density with Lean Mass, Fat Mass, and Physical Activity in Young Overweight and Obese Women.

To examine the associations between bone mineral density (BMD), body composition and habitual physical activity in women who are overweight/obese. We measured whole-body bone, and body composition (lean mass, fat mass, and total fat percent) via dual-energy x-ray absorptiometry (model General Electric Lunar whole-body scanner) in a diverse group of women (N=48, age 26.6+/-4.7 years, 63% Black) living in an urban setting. The relations between BMD with total fat percent [%]), lean mass (kg), fat mass (kg), and physical activity were examined using Pearson correlations and multiple linear regression models, adjusted for race, age, and dietary calcium. BMD was positively correlated with lean mass (r=0.43, p=0.002) and negatively correlated with total fat percentage (r=-0.31, p=0.03). Multiple linear regression models indicated BMD was positively associated with lean mass (ß: 0.007, p<0.001), and negatively associated with fat mass (kg) and total fat percentage (ß: -0.003, p=0.03; ß: -0.004, p=0.03, respectively). When stratified by race, these relations were maintained in white women but only lean mass in Black women. When stratified by age, the positive correlation between BMD and lean mass was significant in younger women (<30y) only. There were no significant relationships between BMD and any physical activity measures. Our results indicate that in young women who are overweight/obese BMD is significantly associated with body composition, both lean mass and total fat percentage, but not habitual physical activity. An emphasis on lean mass accrual may be valuable for young women, particularly Black women, to improve bone health.

Age, Sex, and Race/Ethnicity Associations between Fat Mass and Lean Mass with Bone Mineral Density: NHANES Data.

Rising rates of obesity and osteoporosis have public health implications; hence, understanding the relationships between body composition (fat mass (FM) and lean mass (LM)) and bone mineral density (BMD) is important. The purpose of this study is to investigate these associations in a large representative sample. A cross-sectional analysis was conducted using National Health and Nutrition Examination Survey participants (n = 1717, age 44.1 ± 14.2 years) who had complete dual energy x-ray absorptiometry (total BMD g/cm2, FM kg, and LM kg) and covariate data. Hierarchical linear regression models were fitted, controlling for demographic and behavioral covariates. Stratum-specific models were fitted by race, sex, and age group. Significant negative associations were found for FM and BMD (ß = -0.003) and significant positive associations for LM and BMD (ß = 0.007). Stratum-specific analyses by race were consistent between groups, while variations in negative association magnitudes were seen in FM for sex (males ß = -0.005 vs. females ß = -0.002) and age (under 45 years of age ß = -0.005 vs. 45 years and older ß = -0.002). Consistent positive linear associations in total and stratum-specified models between LM and BMD could suggest a potential mechanical influence on bone health. The biological mechanisms driving the magnitude variations between FM and BMD by sex and age require more investigation.

Associations between Walk Score and objective measures of physical activity in urban overweight and obese women.

The purpose of this study was to examine associations between the Walk Score and physical activity in young, overweight/obese urban women. Project Health included 45 White or African American women (BMI 31.5±3.9 kg/m2; age 26.5±4.6 years; 62% African American) living in the Boston area. An accelerometer estimated steps/day and mins/day in light physical activity (100-2019 counts-per-minute) and moderate-to-vigorous-physical activity (≥2020 cpm). Walk Score was used to estimate the walkability of home address by analyzing proximity to nearby amenities. General linear regression models estimated associations between total Walk Score and physical activity (light physical activity, moderate-to-vigorous-physical activity, steps, total activity counts, METs), adjusting for body mass index, age, race/ethnicity, seasonality, wear time, employment and student status. For physical activity variables that had significant associations with Walk Score (steps/day and steps/min), regression models were estimated for Walk Score sub-scores (parks, grocery, errands, shopping, dining/drinking, culture/entertainment and schools). Logistic regression models estimated the odds of meeting the guidelines for steps (≥10,000/day) and moderate-to-vigorous-physical activity (≥150mins MVPA/week) based on Walk Score. Participants had a Walk Score of 63.9±26.4, took 14,143±3,934 steps/day, and spent 206.2±66.0 mins/day in light physical activity and 46.7±17.5 mins/day in moderate-to-vigorous- physical activity. Walk Score was significantly and positively associated with steps/day (ß = 51.4, p = 0.01) and steps/min (ß = 0.06, p = 0.009) but was not associated with mins/day of light physical activity, moderate-to-vigorous-physical activity, total activity counts or METs. Parks, grocery, errands, shopping, dining/drinking, and culture/entertainment Walk Score sub-scores were significantly associated with steps and steps/min (all p<0.05), but not significantly associated for schools. Participants who lived in higher Walk Score neighborhoods were more likely to meet the step guidelines (OR, 95% CI: 1.59, 1.04-2.99) and moderate-to-vigorous-physical activity guidelines (1.63, 1.06-3.02), respectively, per 10-unit increase in Walk Score. These results indicate that living in a more walkable neighborhood may support walking behavior in young, urban-dwelling overweight/obese women and provide further evidence for the expanded use of urban planning and transportation policies to improve the walkability of urban neighborhoods.

Efficacy of a Culturally Based Parenting Intervention: Strengthening Open Communication Between Mexican-Heritage Parents and Adolescent Children.

This article presents the results of an initial efficacy trial of a parenting intervention, Familias: Preparando la Nueva Generación (FPNG), used to strengthen parenting practices, specifically, open family communication. Using community-based participatory research, including stakeholder involvement, the FPNG curriculum was developed, evaluated for feasibility, and revised to complement the classroom-based keepin' itREAL youth substance-use prevention program. FPNG focuses on family influences that characterize Mexican-heritage youth and families, including the impact of acculturation. The 9 middle schools were block-randomized into 3 groups: parents and youth (PY), youth only (Y), and control (C) conditions. Parents of 7th grade youth (N = 393, 82.8% mothers) completed self-report surveys at baseline and immediately following the intervention. Structural equation model analyses confirmed that PY parents reported significantly greater levels of open family communication at the follow-up compared with Y parents; C parents were not significantly different from Y parents at follow-up. The inclusion of parents in adolescent-focused preventive interventions might increase the effect size of an original and efficacious youth prevention intervention.