Age Trajectories of Grip Strength: Cross-Sectional and Longitudinal Data Among 8,342 Danes Aged 46 to 102

Purpose

The purpose is to study the age trajectory of hand-grip strength after the age of 45 years.

Methods

In this study, we use data from three large nationwide population-based surveys of Danes aged 45 to 102 years with a total of 8342 participants with grip-strength measurements and up to 4 years of follow-up. Grip strength was measured by using a portable hand dynamometer.

Results

Grip strength declines throughout life for both males and females, but among the oldest women, the longitudinal curve reaches a horizontal plateau. The course of the decline is estimated by using full information in the longitudinal data and is found to be almost linear in the age span of 50 to 85 years. In this age span, mean annual grip-strength loss is estimated to be 0.59 (0.02) (SE) kg for men and 0.31 (0.01) kg for women.

Conclusion

This study confirms the previously reported grip-strength decline with increasing age. Estimates were obtained by using full-information methods from large population-representative studies. Equations of expected grip strength, as well as tables with sex-, age-, and height-stratified reference data, provide an opportunity to include grip-strength measurement in clinical care in similar populations.

Introduction

Cross-sectional and longitudinal studies showed that muscle strength in adults declines with increasing age among both men and women 1, 2, 3, 4, 5, 6, 7, 8. Hand-grip strength is an estimate of isometric strength in the upper extremity, but also correlates with strength in other muscle groups (9) and therefore has been taken as an estimate of “overall strength.” Measurement of grip strength therefore has been included in many aging studies. Also, grip strength has proved to be a strong predictor of phenotypes of special interest among the elderly, e.g., physical functioning and disability 10, 11, 12, morbidity 1, 13, and mortality 14, 15, 16, 17. The instrument to measure grip strength, the handheld dynamometer, is inexpensive, easily portable, simple and quick to use, and thus feasible in home-based settings, which is crucial for response rates in studies of the elderly. Because the test does not necessarily require that participants stand up, grip strength can be determined for the elderly with impairments in lower-extremity functioning. Although affected by the physical and cognitive state of the elderly, the possibility of participating in this performance measure is not inherently limited to better-functioning individuals; therefore, it has been used with high participation rates, even among nonagenarians (10). Furthermore, because no ceiling effect has been observed among the younger and/or predisabled elderly, it also can be used for discriminating function among the middle aged (18).

In cross-sectional and longitudinal studies, grip strength has been reported to decline from approximately 30 years of age 3, 8. Based mostly on cross-sectional studies, mean annual loss in grip strength among healthy people from age 30 to 70 years has been estimated to be 0.5% to 1% of the strength at 30 years of age (19). From cross-sectional and longitudinal studies, the course of the decline was reported to accelerate with increasing age 1, 3, 4, 5. However, the annual loss may be underestimated in these studies because no attempt was made to take into account the problem of selective dropout caused by mortality and morbidity that is an inherent problem in aging studies. Furthermore, these studies included only a few participants aged 85 years and older, and two studies included only males 1, 5. In the present study, we describe the course of decline in grip strength from age 45 by using cross-sectional data from three large nationwide surveys of middle-aged, elderly, and oldest-old individuals, as well as 2- and 4-year follow-up data among the elderly and oldest old. Results can be used for studying differences in health and functioning of the elderly across regions and countries, as well as background data if grip-strength measurement is adopted as a routine measure in clinical assessment of the elderly.