Lifestyle physical activity interventions

To identify and quantify the major external (nongenetic) factors that contribute to death in the United States. Articles published between 1977 and 1993 were identified through MEDLINE searches, reference citations, and expert consultation. Government reports and complications of vital statistics and surveillance data were also obtained. Sources selected were those that were often cited and those that indicated a quantitative assessment of the relative contributions of various factors to mortality and morbidity. Data used were those for which specific methodological assumptions were stated. A table quantifying the contributions of leading factors was constructed using actual counts, generally accepted estimates, and calculated estimates that were developed by summing various individual estimates and correcting to avoid double counting. For the factors of greatest complexity and uncertainty (diet and activity patterns and toxic agents), a conservative approach was taken by choosing the lower boundaries of the various estimates. The most prominent contributors to mortality in the United States in 1990 were tobacco (an estimated 400,000 deaths), diet and activity patterns (300,000), alcohol (100,000), microbial agents (90,000), toxic agents (60,000), firearms (35,000), sexual behavior (30,000), motor vehicles (25,000), and illicit use of drugs (20,000). Socioeconomic status and access to medical care are also important contributors, but difficult to quantify independent of the other factors cited. Because the studies reviewed used different approaches to derive estimates, the stated numbers should be viewed as first approximations. Approximately half of all deaths that occurred in 1990 could be attributed to the factors identified. Although no attempt was made to further quantify the impact of these factors on morbidity and quality of life, the public health burden they impose is considerable and offers guidance for shaping health policy priorities.

This study examined predictors of adoption and maintenance of vigorous physical activity over time in a sample of 1,719 randomly selected women and men. Based on reported frequency of vigorous exercise in a mail survey at baseline, subjects were classified as sedentary (zero sessions per week), intermediate (one to two sessions per week), or active (three or more sessions per week). On the same survey subjects reported on 25 potential determinants of physical activity based on a comprehensive learning model. Twenty-four months later, 85% of subjects were resurveyed, and their physical activity levels were classified. Within each baseline category and gender subgroup, predictors of follow-up physical activity were identified. In multivariate analyses, adoption of vigorous exercise by sedentary men was predicted by self-efficacy, age (inverse), and neighborhood environment (inverse). Adoption by sedentary women was predicted by education, self-efficacy, and friend and family support for exercise. Maintenance of vigorous physical activity was predicted by self-efficacy and age (inverse) for initially active men and by education for initially active women. These results suggest that factors influencing adoption are different for men and women, and there may be different factors influencing adoption versus maintenance of vigorous physical activity.