Childhood socioeconomic disadvantage is associated with lower mortality in older Japanese men: the JAGES cohort study

Abstract

Background: Childhood socioeconomic disadvantage has been previously linked to increased mortality risk in adulthood. However, most previous studies have focused on middle-aged adults in Western contexts. Here, we sought to examine the association between childhood socioeconomic status (SES) and mortality among healthy older Japanese adults. Methods: We conducted a 3-year follow-up of participants in the Japan Gerontological Evaluation Study (JAGES), a population-based cohort of 65- to 103-year-old Japanese adults. Childhood SES was assessed by survey at baseline. Mortality from 2010 to 2013 was analysed for 15 449 respondents (7143 men and 8306 women). Cox regression models were used to estimate hazard ratios (HR) for risk of death. Results: A total of 754 deaths occurred during the 3-year follow-up. Lower childhood SES was significantly associated with lower mortality in men, but not in women. Compared with men growing up in more advantaged childhood socioeconomic circumstances, the age-adjusted HR for men from low childhood SES backgrounds was 0.75 [95% confidence interval (CI): 0.56-1.00]. The association remained significant after adjustment for height, education, adult SES, municipalities of residence, health behaviours, disease status and current social relationships (HR = 0.64; 95% CI 0.47-0.87). This association was stronger among men aged 75 years or older, HR = 0.67 (95% CI: 0.47-0.95), compared with men aged 65- 74 years, HR = 0.90 (95% CI: 0.54-1.51). Conclusions: Childhood socioeconomic disadvantage is associated with lower mortality among men aged 75 years or older, which may be due to selective survival, or alternatively to childhood physical training or postwar calorie restriction in this generation of Japanese males.