Objective   To explore associations of absolute grip strength and grip strength-weight index (absolute grip strength/weight × 100) with the risk of metabolic syndrome (MS) among adult rural residents and to provide evidences for early identification and comprehensive prevention of MS in the population.

  Methods  The participants of the study were 3 997 adult (18 – 80 years) residents in 39 rural villages of Pingyin county, Shandong province. The participants′ complete data on anthropometric measurements (including grip strength) and MS-related physical examination and laboratory test were collected during a period from October 2017 through September 2019. The MS risk associated absolute grip strength and grip strength-weight index were estimated based on statistical analyses on the data collected.

  Results  The prevalence of MS among the participants was 18.71% (18.15% for males and 18.97% for females). The absolute grip strength of male participants with MS was significantly higher than that of males without MS (38.53 ± 8.32 kg vs. 36.67 ± 9.16 kg) but the female participants with MS had a significantly lower absolute grip strength than the females without MS (24.28 ± 5.38 kg vs. 25.07 ± 5.40 kg) (both P < 0.01); in comparison with that of the participants without MS, the grip strength-weight index of the participants with MS were significantly lower (40.66 ± 11.21 vs. 46.30 ± 12.36 for the all, 50.39 ± 10.86 vs. 55.74 ± 12.96 for the males, and 36.45 ± 8.40 vs. 41.99 ± 9.30 for the females; all P < 0.001). Correlation analysis results demonstrated that among the male participants, the absolute grip strength was positively correlated with body mass index (BMI), diastolic blood pressure (DBP) and triglyceride (TG) (P < 0.001) but reversely correlated with systolic blood pressure (SBP) and high density lipoprotein cholesterol (HDL-C) (P < 0.05); while the grip strength-weight index was positively correlated with HDL-C (r = 0.20, P < 0.001) and reversely correlated with BMI, SBP, TG and fasting plasma glucose (FPG) (P < 0.001); the results also revealed that among the female participants, the absolute grip strength was positively correlated with BMI (r = 0.13, P < 0.001) but reversely correlated with SBP, HDL-C, and FPG (all P < 0.01), whereas the grip strength-weight index was positively correlated with HDL-C (r = 0.15, P < 0.001) but reversely correlated with BMI, SBP, DBP, TG, and FPG (all P < 0.001). The results of Chi-square test-based trend analyses revealed that with the increment of grip strength-weight index, the prevalence of MS, overweight and/or obesity, and dyslipidemia increased and the prevalence of hypertension decreased significantly among the male participants (all P < 0.05); while among the female participants, the prevalence of overweight and/or obesity increased and the prevalence of MS, hypertension and hyperglycemia decreased with the increment of absolute grip strength (all P < 0.01); the prevalence of MS, overweight and/or obesity, hypertension, dyslipidemia, and hyperglycemia decreased significantly with the increment of grip strength-weight index in both the male and female participants (all P < 0.001). After adjusting for age, education, smoking, alcohol drinking, physical activity, and family history of cardiovascular disease/hypertension/hyperlipidemia/diabetes, the results of multivariate logistic regression analysis indicated that the participants with the absolute grip strength values within the highest quartile had an increased risk of overweight and/or obesity (for the males: odds ratio OR = 2.34, for the females: OR = 1.90; both P < 0.05) compared to those with the values within the lowest quartile; the results also revealed decreased risks of MS (OR = 0.16 and 0.19), overweight and/or obesity (OR = 0.12 and 0.09), hypertension (OR = 0.51 and 0.42), dyslipidemia (OR = 0.25 and 0.48), and hyperglycemia (OR = 0.36 and 0.55) in both male and female participants with the grip strength-weight index values within the highest quartile compared to the male and female participants with the index values within the lowest quartile after adjusting potential confounders mentioned above (all P < 0.001).

  Conclusion   The grip strength-weight index is inversely associated with MS and its components significantly among rural adult residents and the index could be used as an indicator in MS screening.