A proposal for reference values of hand grip strength in women with different body mass indexes

Abstract Background & aims : Hand grip strength (HGS) is frequently used in clinical practice, resulting in a potential marker of nutritional status. This study aimed to develop reference values of HGS in Italian women with different categories of body mass index (BMI). Additionally, the main predictors of HGS were identified. Methods : A cross-sectional study was conducted in Italian women aged between 16 and 55 years with different categories of BMI at the Department of Clinical Medicine and Surgery, Federico II University Hospital, Naples Italy. The whole sample was divided into tertiles according to BMI: 15-17.29 kg/m² (T1), 17.3-19.9 kg/m² (T2) and 20-25 kg/m² (T3). Anthropometry, bioimpedance analysis (BIA) and muscle strength by an HGS test were evaluated. The cutoff values for HGS were developed for all participants and stratified by age group. Finally, a multivariate linear regression analysis was performed to assess the main predictors of HGS. Results : A total of 529 women with a mean age of 23.2 ±7.0 years and an average BMI of 18.9 ± 2.5 kg/m2 were analyzed. HGS was higher for the dominant hand than for the nondominant hand in all BMI tertiles. On both sides, according to age groups, HGS increased with increasing age in T1 and T3, while it increased in the women aged between 20 and 30 years in T2 only. Multivariate linear regression analysis showed that predictors of HGS varied according to tertiles. Specifically, we found that body weight (R²=0.252) was the main predictor in T1, whereas phase angle (PhA) was the main determinant in both T2 (R²=0.240) and T3 (R²=0.216). Conclusion : This study defined the normal reference values of HGS in Italian women with different BMI ranges, stratifying the sample group by age. Additionally, the main predictors of HGS were assessed for each BMI tertile. In primary malnutrition (T1), the main predictor of HGS was body weight, whereas in the other two tertiles (T2-T3), the PhA was the main predictor of HGS.