Associations of dietary and physical activity behaviors with handgrip strength in middle-aged and older adults: a prospective cohort study

Data regarding the association between dietary behaviors and handgrip strength (HS) are limited. The current study aimed to evaluate the hypothesis that dietary patterns, eating behaviors, and physical activity are associated with HS measured in later life. The study used data of 2,615 Korean adults (1,101 men and 1,514 women aged 43-74 years) without sarcopenia, who participated in a population-based prospective cohort study and completed questionnaire-based interviews and health examinations during the period of 2005 - 2014. Baseline (year 2005 - 2006) information on eating behaviors and physical exercise was obtained with dietary data, which were obtained via a food frequency questionnaire and used for dietary pattern analysis. The study outcome was HS measured at 8-year follow-up (year 2013 - 2014). Factor analysis, linear regression analysis, and modified Poisson regression analysis were performed. Sex-specific factor analysis revealed two dietary patterns labeled as "a Balanced Diet" characterized by a high intake of a variety of foods, and "a Refined Carb Diet" characterized by a high intake of refined grain foods in both men and women. In the multiple regression analysis, a higher factor score (FS) for a Balanced Diet was associated with increasing HS among women (P < 0.05) whereas a higher FS for a Refined Carb Diet was associated with decreasing HS among men (P < 0.05). Among women, slow eating behavior and irregular eating of meals were associated with decreasing HS (P < 0.05) whereas the performance of regular exercise was associated with increasing HS (P < 0.01). Similar significant results were observed in the associations with low HS, possible sarcopenia, defined as < 18 kg for women; the multivariable adjusted risk ratios (95% confidence interval) of low HS were 0.86 (0.74, 0.99) for a Balanced Diet, 1.23 (1.09, 1.40) for slow eating behavior, and 0.84 (0.72, 0.97) for regular exercise compared with its corresponding reference. These results suggest that a healthy diet consisting of a variety of foods and regular physical exercise may attenuate aging-related declines in HS and further prevent sarcopenia.