Temporal trends in handgrip strength for older Japanese adults between 1998 and 2017.

OBJECTIVE

to estimate temporal trends in handgrip strength (HGS) for older Japanese adults between 1998 and 2017.

DESIGN AND METHODS

adults aged 60-79 years were included. Annual nationally representative HGS data (n = 176,449) for the 19-year study period were obtained from the Japanese Ministry of Education, Culture, Sports, Science and Technology. Temporal trends in mean HGS were estimated by sample-weighted regression models relating the year of testing to mean HGS. National trends in absolute, percent and standardised HGS were estimated by a post-stratified population-weighting procedure. Temporal trends in variability were estimated as the ratio of coefficients of variation (CVs).

RESULTS

collectively, there was a small improvement in mean HGS of 1.4 kg (95% confidence interval [CI]: 1.3-1.5), 4.5% (95%CI: 4.3-4.7) or 0.27 standard deviations (95%CI: 0.26-0.28) between 1998 and 2017. The rate of improvement progressively increased over time, with more recent values (post-2008) 1.5-fold larger than earlier values. Gender- and age-related temporal differences were negligible. Variability in HGS declined substantially over time (ratio of CVs [95%CI]: 0.88 [0.86-0.90]), with declines 1.9-fold larger in women compared to men and 1.7-fold larger in 70- to 79-year-olds compared to 60- to 69-year-olds.

CONCLUSIONS

there has been a small, progressive improvement in mean HGS for older Japanese adults since 1998, which is suggestive of a corresponding improvement in strength capacity. The substantial decline in variability indicates that the improvement in mean HGS was not uniform across the population.