Handgrip Strength and Related Factors in Postmenopausal Women

In This Article

Abstract and Introduction

Abstract

Objective: This study aimed to evaluate the prevalence of dynapenia and factors related to low dominant handgrip strength (HGS) in postmenopausal women.

Methods: A cross-sectional study was performed on 249 postmenopausal women aged 50 to 84 years. The following variables were recorded: age, age at menopause, smoking status, and the HGS measured with a digital dynamometer, body mass index, and adiposity assessed by bioelectric impedance. The physical activity level was evaluated by using the International Physical Activity Questionnaire. Bone mineral density was reported as T-scores, and blood biochemical parameters (calcium, phosphorus, vitamin D, and parathormone levels) were measured.

Results: 31.3% of women had dynapenia, and those aged ≥65 years had lower HGS (P < 0.001). Age at menopause was also associated with HGS, with those with menopause < 51 showing lower HGS (P = 0.005). Likewise, fat content ≥ 40%, and osteopenia/osteoporosis were also related to lower strength (P < 0.001). There was no statistically significant difference among HGS with respect to body mass index, smoking status, and plasma levels of vitamin D. A logistic regression model with lower Akaine Information Criterion showed that for every year in age and for each 1% of adiposity, women were more likely to have dynapenia with odd ratio (OR): 1.09; 95% and confidence interval (CI): 1.04 to 1.14 and OR: 1.06; 95% CI: 1.00 to 1.13, respectively. Conversely, women with higher femoral neck T-score were less likely to have dynapenia (OR: 0.53; 95% CI: 0.35–0.78).

Conclusions: HGS was associated with age at menopause, bone mineral density, and adiposity adjusted by age. The age and adiposity were significantly associated with a higher risk of dynapenia, whereas women with higher femoral neck T-score were less likely to have dynapenia.

Introduction

Muscle strength is an essential function of the human body, being a relevant component of health and physical fitness. It also refers to the ability of a muscle or muscle group to exert force against a resistance. Muscle strength is involved in many activities, daily tasks, maintenance of functional independence, and autonomy. Thus, regular physical activity adapted according to age is a preventive recommendation for healthy aging.^[1–3] Dynapenia defines the age-related loss of muscle strength, is the primary indicator of sarcopenia, and is a prognostic indicator of functional impairments in older adults.^[4] Thus, it is very important to maintain muscle strength to reduce functional limitations with age. The grip strength is considered a biomarker of frailty, in which there is an increase in an individual's vulnerability for developing dependency and/or mortality.^[5–7] In this context, it is convenient to dissociate the muscle mass reduction (sarcopenia) from the concept of muscle strength reduction (dynapenia).^[8]

The pathophysiological mechanisms of muscle weakness can be compartmentalized into two factors. First the impairment of muscle system causes a deficit in the skeletal muscle force production and second the nervous system impairment that decreases the ability of voluntary muscle activation. Subsequently, it produces functional limitations and risk of physical disability.^[9] Muscle-skeletal changes are associated with aging, although other factors are involved in maintaining muscle strength and mass, such as hormonal profile, physical activity level, and nutritional status. So that old age, postmenopausal women, low body mass index (BMI), and low physical activity have been highly associated with dynapenia.^[8–10] Handgrip strength (HGS) measured with a hand dynamometer is a simple and accurate technique to assess muscle strength which is moderately related to muscular strength in other body sites. Therefore, it is considered a surrogate measure of more complicated approaches, such as arm and leg strength.^[11] The purpose of the current study was to investigate the prevalence of dynapenia and investigate factors associated with low HGS in postmenopausal women.

Table 1. Biochemical parameters reported as mean ± standard deviation
Parameters	Estimate (n = 249)	95% confidence Interval	Reference ranges
Vitamin D	33.7 ± 11.8	32.2–35.2	30–100 ng/mL
Calcium	9.59 ± 0.35	9.5–9.6	8.7–10.4 mg/dL
Phosphorous	3.6 ± 0.4	3.6–3.7	2.5–4.5 mg/dL
Parathormone	44.0 ± 14.9	42.2–45.9	15–65 pg/mL

Table 2. Differences between hand grip strength (mean ± standard deviation) with regards to general characteristics of studied women, and vitamin D status
Parameters	Categories	n = 249	HGS	P value	95% CI (mean differences)
Age (y)	<65 ≥65	132 117	23.7 ± 3.8 21.0 ± 3.8	<0.001	[1.7; 3.7]
Age at menopause (y)	<51 ≥51	156 93	21.9 ± 3.8 23.4 ± 4.3	0.005	[−2.6; −0.5]
Smoking	Never Smoker	202 47	22.5 ± 4.1 22.3 ± 4.0	0.846	[−1.4; 1.2]
BMI (kg/m²)	Low Normal High	4 143 102	22.1 ± 3.2 22.6 ± 4.0 22.2 ± 4.1	0.691	[−4.7; 3.5] Reference [−1.5; 0.6]
Adiposity (%)	<40 ≥40	109 140	23.7 ± 4.3 21.5 ± 3.5	<0.001	[1.1; 3.2]
Vitamin D (ng/mL)	<30 ≥30	106 143	22.2 ± 3.6 22.6 ± 4.4	0.503	[−1.3; 0.7]
Physical activity	Low Moderate High	108 132 9	21.8 ± 3.5 22.8 ± 4.3 24.9 ± 5.3	0.027	Reference [−0.01; 2.1] [0.4; 5.9]
BMD Lumbar spine	Normal Osteopenia Osteoporosis	68 116 65	24.5 ± 3.7 21.6 ± 4.1 21.7 ± 3.6	<0.001	Reference [−4.1; −1.7] [−4.2; −1.5]
BMD total hip	Normal Osteopenia Osteoporosis	103 134 12	23.6 ± 3.9 21.6 ± 4.1 21.2 ± 2.2	<0.001	Reference [−3.0; −0.9] [−4.9; −0.1]
BMD Femoral Neck	Normal Osteopenia Osteoporosis	83 156 10	23.9 ± 3.6 21.7 ± 4.1 22.2 ± 3.1	<0.001	reference [−3.3; −1.1] [−4.4; 0.9]
BMD, bone mineral density; BMI, body mass index; CI, confidence interval; HSG, handgrip strength.

Table 3. Pearson correlation analyses between handgrip strength and age, age at menopause, adiposity, and bone mineral density (T-score)
Handgrip strength
Covariates	r (Pearson correlation)	P value	Partial correlations	P value
Age	−0.340	<0.001	-	-
Age at menopause	0.130	0.035	0.166	0.009
Body mass index	0.002	0.970	0.050	0.432
Adiposity	−0.270	<0.001	−0.225	<0.001
Vitamin D	0.041	0.520	0.120	0.058
Calcium	0.110	0.075	0.124	0.051
Phosphorus	0.042	0.510	−0.005	0.941
Parathormone	−0.010	0.870	0.025	0.699
T-score lumbar spine	0.260	<0.001	0.178	0.005
T-score femoral neck	0.260	<0.001	0.223	<0.001
T-score total hip	0.270	<0.001	0.205	0.001