The distribution of TV viewing among BWHS participants at baseline in 1995 was 0–1 hour/day, 9.7% (n=1711); 1–2 hours/day, 37.1% (n=6561); 3–4 hours/day, 37.4% (n=6615); and 5+ hours/day, 15.9% (n=2810). In 1997, when the question was modified to include “videos”, the distribution of TV viewing shifted slightly upwards, with 7.4% reporting 0–1 hours/day, 34.7% reporting 1–2 hours/day, 38.3% reporting 3–4 hours/day, and 19.5% reporting 5+ hours/day. The distribution in 1999, when the query specified “videos and home computer”, was almost identical to that in 1997.
As shown in , compared to women living in the lowest quintile of neighborhood walkability, women in the highest quintile were younger, had higher energy intake and fewer years of education, and were more likely to be married, be current smokers, and walk for transport. Compared to women living in the lowest quintile of neighborhood SES, women in the highest quintile were older, had lower BMI and energy intake, had more years of education, and were more likely to be married and to participate in vigorous activity and walking for exercise. They were less likely to smoke, walk for transport, or report a chronic disease.
Characteristics in the lowest and highest quintiles of walkability and neighborhood SES scores, BWHS 1995a
In model 1, the odds ratios for heavy TV viewing were 1.22 and 1.25 for the two highest quintiles of neighborhood walkability relative to the lowest quintile (). When neighborhood SES was added to model 2, both odds ratios were reduced to 1.04. Neighborhood SES was inversely associated with heavy TV viewing with and without adjustment for neighborhood walkability, and tests for linear trends were significant in both models: in model 2, the odds ratio for the highest quintile of SES was 0.66 (95% CI 0.54–0.81).
Odds of TV viewing 5+ hours/day compared to 0–1 hour/day by quintile of neighborhood walkability and neighborhood SES
Odds ratios from model 2 associated with the walkability and SES scores did not differ significantly by strata of age, city, years of education, or hours/week of walking for transport (data not shown). The effect of neighborhood SES on TV viewing was more pronounced among those who reported <3 hrs/week of vigorous physical activity (OR for 5th compared to 1st quintile of SES= 0.65, 95% CI 0.52–0.80) than those who reported 3+hours/week (OR=0.81, 95% CI 0.54–1.20), although the odds ratios did not differ in a statistically significant way (p for interaction =0.80).
When the analysis was confined to the 45% of women with consistent TV viewing habits (the same level of TV viewing reported on all questionnaires), results were similar to those from the full cohort. Estimates were also similar within strata of questionnaire cycle (1995–1997, 1997–1999, 1999–2001) (data not shown).