Strong hands, strong heart? New evidence suggests greater handgrip strength lowers the risk of heart disease.
Handgrip strength is an indicator of healthy aging and has beenassociated with various chronic disease outcomes in observational studies. For example, greater grip strength was linked to a lower risk of diabetes, metabolic disease, heart disease, and death. However, observational studies do not consider underlying health issues and may be confounded by body size and body mass index.
Research by Xu and Hao published in Scientific Reports aimed to better understand the effect of handgrip strength on cardiovascular disease risk using a Mendelian Randomization (MR) study. MR studies use genetic variants as markers to explore the effect of environmental exposures on health and are less prone to confounding effects from non-genetic factors. Using data from a recent genome-wide association study from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium, investigators examined two genetic single nucleotide polymorphisms (SNPs) related to handgrip strength. These SNPs, called rs3121278 and rs752045, are in BMS1L and CSMD1 genes, respectively. Both are found to contribute independently to grip strength at genome-wide significance level (p< 5*10-8). Association of the two SNPs with disease and observable characteristic (phenotypic) data were gathered from publicly available databases. The effect of each SNP on heart disease/heart attack was weighted by its effect on handgrip strength. These estimates were then pooled to give a combined measure for the effect of increased handgrip strength heart disease/heart attack risk.
Statistical analysis showed that a 1-kilogram increase in genetically determined handgrip strength reduced the odds of heart disease by 6% and of heart attack by 7%. Handgrip strength was not significantly associated with type 2 diabetes, body mass index, or cholesterol levels. Furthermore, an inverse causal relationship between handgrip strength and heart disease or heart attack indicates that improvement of muscle strength via resistance training may be important for heart health. However, investigators note that due to the use of combined genome-wide data, they were not able to determine whether the effect of handgrip strength on heart disease varies by sex or age. However, a truly causal effect should be stable.
In conclusion, this study is the first MR study on handgrip strength and gives evidence that greater handgrip strength lowers heart disease risk. It also supports the ideathat increased physical activity is important for maintaining muscular strength and improving heart health.
Written By: Cindi A. Hoover, Ph.D.