Purpose：This study aimed（1） to examine the longitudinal trajectories in objectively measured physical activity（PA）;（2） to identify unknown（i.e.,latent） subgroups with distinct trajectories;and（3） to examine...Purpose：This study aimed（1） to examine the longitudinal trajectories in objectively measured physical activity（PA）;（2） to identify unknown（i.e.,latent） subgroups with distinct trajectories;and（3） to examine the correlates of latent subgroups among community dwelling women.Methods：The study sample included a total of 669 women from the Women＇s Injury Study,a 5-year prospective cohort study conducted from2007 in the Southwest Central region of the US.Pedometer-based step-count data across 18 consecutive months were fitte to a latent growth model（LGM） and a latent class growth model（LCGM）.Baseline characteristics were regressed on latent class membership.Results：The longitudinal change in PA was best fi to a piecewise LGM with seasonal transitions.Significant y increased and decreased levels of PA were observed during the spring,fall,and winter,respectively（p〈0.001）.Three latent subgroups with distinct PA trajectories were identifie（low-active（46.8%）,somewhat-active（41.3%）,and active（11.9%））.Age and body fat percentage at the baseline significant y explained the likelihoods of being in low-active subgroup.Conclusion：Seasonal variations in PA among women were observed but may not be practically significant A relatively large portion of the sample showed low levels of PA for long periods.Intervention strategies should be considered for women who are overweight or obese,and aged 〉40 years old to promote PA during the life course.展开更多
基金supported by the grant from the National Institutes of Health–National Institute of Arthritis and Musculoskeletal and Skin Diseases(No.R01 AR052459)
文摘Purpose：This study aimed（1） to examine the longitudinal trajectories in objectively measured physical activity（PA）;（2） to identify unknown（i.e.,latent） subgroups with distinct trajectories;and（3） to examine the correlates of latent subgroups among community dwelling women.Methods：The study sample included a total of 669 women from the Women＇s Injury Study,a 5-year prospective cohort study conducted from2007 in the Southwest Central region of the US.Pedometer-based step-count data across 18 consecutive months were fitte to a latent growth model（LGM） and a latent class growth model（LCGM）.Baseline characteristics were regressed on latent class membership.Results：The longitudinal change in PA was best fi to a piecewise LGM with seasonal transitions.Significant y increased and decreased levels of PA were observed during the spring,fall,and winter,respectively（p〈0.001）.Three latent subgroups with distinct PA trajectories were identifie（low-active（46.8%）,somewhat-active（41.3%）,and active（11.9%））.Age and body fat percentage at the baseline significant y explained the likelihoods of being in low-active subgroup.Conclusion：Seasonal variations in PA among women were observed but may not be practically significant A relatively large portion of the sample showed low levels of PA for long periods.Intervention strategies should be considered for women who are overweight or obese,and aged 〉40 years old to promote PA during the life course.
