The increasing prevalence of diabetes among adults in both developed and low-income countries has become a major concern for health epidemiologists [1]. T2D results from a complex interplay of lifestyle, environmental, and genetic factors [2]. Its high prevalence is alarming due to increased healthcare use and serious health consequences, including micro- and macrovascular complications (neuropathy, nephropathy, retinopathy, cardiovascular disease), which impair quality of life and lead to greater morbidity and mortality [[2], [3], [4], [5], [6]]. The chronic complications of T2D also create a major economic burden, such as lost productivity and healthcare costs, which in France exceeded €8.5 billion in 2013 [7]. Effective prevention and early screening strategies are therefore essential.

A large body of research has demonstrated an association between low muscle strength, as assessed by handgrip strength (HGS), and an increased risk of developing T2D [[8], [9], [10], [11], [12]]. Increasing muscle strength may reduce the risk of insulin resistance, one of the key factors in the development of T2D [13]. In addition, low HGS has been associated with an increased risk of cardiovascular disease and all-cause mortality [14,15]. The handgrip test is a simple, acceptable, cost-effective, feasible and scalable measure of muscle strength for clinical and population screening and surveillance. It has moderate to high criterion validity and high to very high reliability [16,17]. The handgrip test is considered as a safe procedure for adult populations, including those with chronic conditions [18]. The handgrip test, using specific thresholds, can serve as a rapid and practical approach for healthcare professionals in the early screening of adults at risk of developing T2D.

In a representative sample of 4066 US adults and older Mexicans [19,20], the authors identified optimal age- and sex-specific low-strength thresholds for detecting T2D risk. A subsequent study was conducted in a similar cohort of US adults [10]. Importantly, there is significant interregional and ethnic variations in mean HGS values, as shown by data from the multinational Prospective Urban Rural Epidemiology (PURE) study of 125,462 adults from 21 countries [21]. Such findings highlight the need for sex- and age-specific HGS cut-off points to be established for each country [22]. Currently, there are no criterion-referenced norms for HGS predicting T2D in French adults.

The objective of this study was to establish sex-specific HGS cut-off points for identifying of T2D risk in French adults. The secondary objective was to investigate the relationship between absolute and relative HGS and the incidence of T2D.