Scott B Going

PMID: 17283300;PMCID: PMC2587404;Abstract:

Objective: To examine how "travel by walking" before and after school contributes to total physical activity of adolescent girls. Design: Cross-sectional sample. Setting: Thirty-six middle schools from Arizona, Maryland, Minnesota, Louisiana, California, and South Carolina participating in the Trial of Activity for Adolescent Girls (TAAG). Participants: Seventeen hundred twenty-one sixth-grade girls consented to participate; adequate information was available for 1596 participants (93%). Main Exposure: Travel by walking before school, after school, and before and after school combined assessed from the 3-Day Physical Activity Recall. Main Outcome Measure: Mean minutes of physical activity measured by accelerometry were estimated for total physical activity (light, moderate, vigorous), moderate to vigorous activity (MVPA), and MVPA of 3 metabolic equivalents. Results: Travel by walking was reported by 14% of participants before school and 18% after school. Girls who reported travel by walking before and after school (combined) had 13.7 more minutes (95% confidence interval, 1.2-26.3) of total physical activity and 4.7 more minutes (95% confidence interval, 2.2-7.2) of MVPA than girls who did not report this activity. Before-school and after-school walkers (but not both) accumulated 2.5 more minutes (95% confidence interval, 0.10-4.9) and 2.2 more minutes (95% confidence interval, 0.24-4.2) of MVPA on an average weekday, respectively, than nonwalkers. Conclusion: Our results provide evidence that walking to and from school increases weekday minutes of total physical activity and MVPA for middle-school girls. ©2007 American Medical Association. All rights reserved.

PMID: 23370026;Abstract:

The purpose of the present study was to measure body composition in a probability sample of adults (≥ 20 years) living in Niterói, State of Rio de Janeiro, Brazil, and to assess the adequacy of the World Health Organization (WHO) recommended body mass index (BMI) cut-offs values for identifying obesity in this population. Anthropometric measures and percentage body fat (%BF) assessments were taken with 550 fasted individuals (352 women). Obesity was classified according to the WHO recommended BMI cut-off values. %BF predictive equations were developed based on the inverse of BMI. BMI and %BF mean values (standard error) were: 25.3kg/m2 (0.3) and 38% (0.4) for women and 25.1kg/m2 (0.3) and 22.1% (0.6) for men. The predicted %BF values (regression of %BF on the inverse of BMI) for each BMI cut-offs of 18.5, 25 and 30kg/m2 were: 26.3%, 38.6% and 44.5% for women and 5.6%, 23.2% and 31.5% for men, respectively. The BMI values for the %BF-estimated obesity cut-off values were 20.5 for men and 25.7kg/m2 for women. Based on the BMI-%BF relationship, the BMI cut-off values recommended by the WHO are not adequate in identifying obesity in adults from this population.

PMID: 20737265;Abstract:

Participants in the observational study of the Women's Health Initiative (WHI) were studied to determine if ethnic differences in femur geometry can help to explain differences in hip fracture rates. Structural differences in femurs of African and Mexican-American women appear to be consistent with lower rates of hip fractures vs. whites. Introduction: Ethnic origin has a major influence on hip fractures, but the underlying etiology is unknown. We evaluated ethnic differences in hip fracture rates among 159,579 postmenopausal participants in the WHI then compared femur bone mineral density (BMD) and geometry among a subset with dual X-ray absorptiometry (DXA) scans of the hip and total body. Methods: The subset included 8,206 non-Hispanic whites, 1,476 African-American (AA), 704 Mexican-American (MA), and 130 Native Americans (NA). Femur geometry derived from hip DXA using hip-structure analysis (HSA) in whites was compared to minority groups after adjustment for age, height, weight, percent lean mass, neck-shaft angle and neck length, hormone use, chronic disease (e.g., diabetes, rheumatoid arthritis, cancer), bone active medications (e.g., corticosteroids, osteoporosis therapies), and clinical center. Results: Both AA and MA women suffered hip fractures at half the rate of whites while NA appeared to be similar to whites. The structural advantage among AA appears to be due to a slightly narrower femur that requires more bone tissue to achieve similar or lower section moduli (SM) vs. whites. This also underlies their higher BMD (reduces region area) and lower buckling ratios (buckling susceptibility). Both MA and NA women had similar advantages vs. whites at the intertrochanter region where cross-sectional area and SM were higher but with no differences at the neck. NA and MA had smaller bending moments vs. whites acting in a fall on the hip (not significant in small NA sample). Buckling ratios of MA did not differ from whites at any region although NA had 4% lower values at the IT region. Conclusion: Differences in the geometry at the proximal femur are consistent with the lower hip fracture rates among AA and MA women compared to whites. © 2010 International Osteoporosis Foundation and National Osteoporosis Foundation.