Aging In Motion: Describing The Longitudinal Decline In Accelerometer-Measured Physical Activity In Older Women

PURPOSE: Few studies have described longitudinal accelerometer-measured physical activity (PA) change in older women. Using up to 4 accelerometer measurements, we examined PA change among older women and identified participant characteristics associated with different trajectories. METHODS: Participants in the Women’s Health Initiative Strong and Healthy trial wore an ActiGraph GT3X+ on the hip for ≥4 of 7 days on up to 4 separate occasions over 7 years. PA measures included light PA, moderate-to-vigorous PA (MVPA), total PA, and daily steps. Linear mixed effects regression models estimated PA change over time. Associations were tested between the following baseline characteristics and PA change: age, race, ethnicity, education, smoking status, alcohol use, living alone, spousal death, general health, physical function, energy/fatigue, social support, purpose in life, vision or hearing impairment, joint pain, depression, multimorbidity, recent weight loss (intentional or unintentional), BMI, and waist circumference. RESULTS: A total of 2,033 women (mean age = 77.1 ± 6.6 years; 62.3% White race, 32.4% Black race, 15.3% Hispanic ethnicity) with ≥2 valid accelerometer wear periods were included. Mean time between baseline and final measurement was 5.2 years (range = 1.5-7.0). Mean [SD] baseline PA measures (min/day or steps/day) were 298.5 [70.0] for light PA, 59.7 [35.3] for MVPA, 357.2 [88.4] for total PA, and 4166 [2209] for steps. The estimated 5-year change in daily PA (95% confidence interval) was -15.4 (-17.8, -13.1) min of light PA, -17.2 (-18.2, -16.3) min of MVPA, -32.9 (-35.6, -30.1) min of total PA, and -1014 (-1078, -951) step counts. Younger age, having ≥1 drink/week, higher physical function and energy/fatigue scores, and lower BMI and waist circumference were associated with less decline in PA. Compared to White women, Black women experienced less decline in light PA but had greater declines in MVPA. CONCLUSIONS: PA levels among older women declined significantly over time, with the largest relative declines observed for MVPA (-30.5%) and daily steps (-25.3%). Various demographic, psychosocial, socioeconomic, and health-related factors were associated with PA trajectories. These findings can help inform tailored public health strategies that promote PA among older women subgroups. Supported by: T32HL079891