Longitudinal assessment of urban form and weight gain in African-American women.

BACKGROUND: Numerous cross-sectional studies have found higher levels of obesity among residents of auto-oriented, sprawling areas compared to residents of more urban areas. PURPOSE: The association between neighborhood urban form and 6-year weight change was prospectively analyzed in the Black Women's Health Study, a cohort study of U.S. black women who enrolled in 1995 and are followed biennially with mailed questionnaires. METHODS: The analysis included 17,968 women who lived in New York City, Chicago, or Los Angeles and were followed from 1995 to 2001. Factor analysis was used to combine variables describing the urban form of participants' residential neighborhoods into an "urbanicity" score. Mixed linear regression models were used to calculate least-squares means for weight change across quintiles of the urbanicity score. Incidence rate ratios (IRRs) and 95% CIs for incident obesity in relation to the urbanicity score among women who were not obese at baseline were derived from Cox regression models. All results were adjusted for age, region, lifestyle factors, and neighborhood SES. Analyses were conducted in 2008-2010. RESULTS: In multivariate analysis, mean weight gain for women in the highest quintile of urbanicity score (most urban) was 0.79 kg less than for those in the lowest quintile, with a significant trend (p=0.003). The IRR for incident obesity in the highest quintile relative to the lowest was 0.83 (95% CI=0.71, 0.97), with a significant trend (p=0.042). CONCLUSIONS: Policies that encourage dense, urban residential development may have a positive role to play in addressing obesity in black women.

Prospective study of urban form and physical activity in the Black Women's Health Study.

The authors used data from the Black Women's Health Study to assess the association between neighborhood urban form and physical activity. Women reported hours/week of utilitarian and exercise walking and of vigorous activity in 1995 and on biennial follow-up questionnaires through 2001. Housing density, road networks, availability of public transit, sidewalks, and parks were characterized for the residential neighborhoods of 20,354 Black Women's Health Study participants living in New York, New York; Chicago, Illinois; and Los Angeles, California. The authors quantified the associations between features of the environment and physical activity using odds ratios for >or=5 relative to <5 hours/week of physical activity. For all women, housing density had the strongest association with utilitarian walking (odds ratio for the most- compared with the least-dense quintile = 2.72, 95% confidence interval: 2.22, 3.31), followed by availability of public transit. Women who moved during follow-up to neighborhoods of lower density were 36% more likely to decrease their levels of utilitarian walking, and those who moved to neighborhoods of higher density were 23% more likely to increase their levels of utilitarian walking, relative to women who moved to neighborhoods of similar density. These data suggest that increases in housing density may lead to increases in utilitarian walking among African-American women.

Multiple stress effects of Vision herbicide, pH, and food on zooplankton and larval amphibian species from forest wetlands.

As part of a multiple-tier research program, interactions of the herbicide Vision (glyphosate) with two stressors, pH and food level, were examined. Effects of the formulated product Vision were tested at two test concentrations (0.75 and 1.50 mg acid equivalent/L), two pH levels (pH 5.5 and 7.5), and under high and low food concentrations. Effects of each stressor alone and in combination were examined using two common wetland taxa: Zooplankton, Simocephalus vetulus, and tadpoles (Gosner stage 25) of Rana pipiens. For S. vetulus, survival, reproduction, and development time were measured; survival was measured for R. pipiens. For both species, significant effects of the herbicide were measured at concentrations lower than the calculated worst-case value for the expected environmental concentration ([EEC], 1.40 mg acid equivalent/L). Moreover, high pH (7.5) increased the toxic effects of the herbicide on all response variables for both species even though it improved reproductive rate of S. vetulus over pH 5.5 in the absence of herbicide. Stress due to low food alone also interacted with pH 5.5 to diminish S. vetulus survival. These results support the general postulate that multiple stress interactions may exacerbate chemical effects on aquatic biota in natural systems.