Sex Differences in the Limit to Deficit Accumulation in Late Middle-Aged and Older Chinese People: Results From the Beijing Longitudinal Study of Aging

Background. On average, as people age, they accumulate more health deficits and have an increased risk of death. The deficit accumulation-based frailty index (FI) can quantify health and its outcomes in aging. Previous studies have suggested that women show higher FI values than men and that the highest FI score (the "limit to frailty") occurs at a value of FI similar to 0.7. Even so, gender differences in the limit to frailty have not been reported. Methods. Data for this analysis were obtained from the Beijing Longitudinal Study of Aging that involved 3,257 community-dwelling Chinese people, aged 55+ years at baseline. The main outcome measure was 5-year mortality. An FI consisting of 35 health-related variables was constructed. The absolute and 99% FI limits were calculated for different age groups and analyzed by sex. Results. The mean level of the FI increased with age and was lower in men than in women (F = 67.87, p < .001). The 99% FI limit leveled off slightly earlier with a relatively lower value in men (60 years; 0.44 +/- 0.02) compared with that in women (65 years; 0.52 +/- 0.04). The highest absolute FI value was 0.61 in men and 0.69 in women. In both groups, people with an FI greater than or equal to the 99% limit showed close to 100% mortality by 5 years. Conclusion. Compared with men, women appeared to better tolerate deficits in health, yielding both relatively lower mortality and higher limit values to the FI. Even so, the FI did not exceed 0.7 in any individual.