Life course trauma and muscle weakness in older adults by gender and race/ethnicity: Results from the U.S. health and Retirement Study.

Muscle weakness, as measured by handgrip strength, is a primary determinant of physical functioning and disability. There is a high burden of muscle weakness in the United States with close to 50 percent of older Americans meeting criteria for clinical muscle weakness. While previous racial/ethnic disparities have been documented among older adults, the extent to which lifecourse trauma shapes muscle strength trajectories is unknown. Using U.S. Health and Retirement Study (N = 20,472, Mean Age = 63.8 years) data on grip strength (2006-2014, up to 3 assessments) and retrospectively reported traumatic events, we fit gender-stratified growth curve models to investigate whether traumatic events experienced across the lifecourse or at distinct sensitive periods (childhood, early/emerging adulthood or mid-life) predicted later-life trajectories of grip strength. There was no association between cumulative trauma and trajectories of grip strength and the main effects for the life stage models were largely null. However, among White women, our results suggest that traumatic events experienced during childhood (β = -0.012; 95% CI = -0.024, 0.0004) compared to middle adulthood are associated with faster declines in grip strength in later life. Traumatic events reported during childhood was related to a slower decline in grip strength over time among Hispanic women compared to that for White women (β = 0.086, 95% CI = 0.044, 0.128). Among Black men, the association between traumatic events during early/emerging adulthood and age-related declines in grip strength was stronger for Black men than for White men (interaction β = -0.070; 95% CI = -0.138, 0.001). Traumatic events experienced during distinct life stages may influence later life declines in grip strength and exacerbate racial inequalities in later life. This study addresses an important gap by investigating the life course social determinants of later life muscle strength, which is a key driver of physical functioning and mobility.