Area deprivation across the life course and physical capability in mid-life: findings from the 1946 British Birth Cohort

Physical capability in later life is influenced by factors occurring across life, yet exposures to area conditions have only been examined cross-sectionally. Data from the MRC National Survey of Health and Development were used to estimate associations of area deprivation (indicated by % of employed people in each area in partly- or un-skilled occupations) at ages 4, 26 and 53 years (residential addresses linked to census data in 1950, 1972 and 1999) with three measures of physical capability at age 53 years: grip strength, standing balance and chair rise time. Cross-classified multilevel models with individuals nested within areas at three ages showed that models assessing a single time-point underestimate total area contributions to physical capability. For balance and chair rise performance, associations with area deprivation in mid-life were robust to adjustment for individual socioeconomic position (SEP) and prior area deprivation [mean percentage change for 1-SD increase (95% confidence interval): balance -7.4% (-12.8, -2.8), chair rise 2.1% (-0.1, 4.3)]. In addition, area deprivation in childhood was related to balance after adjustment for childhood SEP [(-5.1% (-8.7, -1,6)]. Interventions aimed at reducing mid8life disparities in physical capability should target the socioeconomic environment of individuals, for standing balance as early as childhood.