Age and secular effects on muscular strength of indigenous rural adults in Oaxaca, Southern Mexico: 1978–2000

Coming to grips with economic development: Variation in adult hand grip strength during health transition in Vanuatu

OBJECTIVES

To determine whether (1) maximal handgrip strength (HGS) is associated with inter-island level of economic development in Vanuatu, (2) how associations between island of residence and HGS are mediated by age, sex, body size/composition, and individual sociodeomographic variation, and (3) whether HGS is predictive of hypertension.

MATERIAL AND METHODS

HGS was collected from 833 adult (aged 18 and older) men and women on five islands representing a continuum of economic development in Vanuatu. HGS was measured using a handheld dynamometer. Participants were administered in an extensive sociobehavioral questionnaire and were also assessed for height, weight, percent body fat, forearm skinfold thickness, forearm circumference, and blood pressure.

RESULTS

HGS was significantly greater in men than in women regardless of island of residence. HGS was also significantly positively associated with inter-island level of economic development. Grip strength-to-weight ratio was not different across islands except in older individuals, where age-related decline occurred primarily on islands with greater economic development. HGS significantly declined with age in both men and women.

CONCLUSION

HGS is positively associated with modernization in Vanuatu, but the relationship between HGS and modernization is largely due to an association of both variables with increased body size on more modernized islands. Further research on the role of individual variation in diet and physical activity are necessary to clarify the relationship between HGS and modernization.

Age as a moderator of the secular trend for grip strength in Canada and the United States

PURPOSE

To determine whether grip strength changed on average over recent decades at each of two age levels (children and adolescents versus adults) in Canada and the US.

METHODS

For each sex, weighted least squares regression analyses were performed on mean grip strength values as reported in studies conducted from the 1960s onwards.

RESULTS

Grip strength did not change significantly as a function of year tested in children and adolescents, whereas it declined as a negatively accelerated function of year tested in adults.

CONCLUSION

The results are contrary to what might be expected given that body weight has increased in both countries in recent decades and given that grip strength has been found to be positively correlated with body weight. It is suggested that there was a concurrent change in a factor that operated to counteract the effect of increased body weight on grip strength, a prime candidate being a decrease in levels of serum vitamin D. It is also suggested that the secular decline in adult grip strength can be explained by a factor that affects muscular function but which has a long latency period, a prime candidate here being obesity history.