Low BMI and Weak Grip Strength Linked to Reduced Lung Function: Study
Researchers have found in a new study that among middle-aged and older Chinese adults, low body mass index (BMI) and reduced handgrip strength were independently associated with lower peak expiratory flow (PEF). Handgrip strength partly mediated the relationship between BMI and PEF, but the effect was small and of limited clinical significance. The findings do not support recommending specific muscle-strengthening interventions based on this association alone. The study was published in the journal Clinics by Xiaonan Zhang and colleagues.
To examine if peripheral muscle strength can mediate the association between nutritional status and respiratory function, the researchers used nationwide cross-sectional data from the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS). The study sample included 8,784 middle-age and elderly Chinese respondents without previous clinical history of chronic obstructive lung diseases. Clinical assessment measures were taken for BMI, HGS through a hand-held dynamometer, and PEF through a standard peak flow meter.
Low pulmonary function was assessed when there was a predicted PEF%pred value of less than 80%. Logistic multivariable regression analysis was used to assess the independent effects of BMI and HGS on low PEF. In addition, formal mediation analysis was done to quantify the degree to which HGS explains the link between BMI and PEF.
Key findings:
- A cross-sectional assessment of 8,784 middle-aged and older subjects found that 671 subjects satisfied the criteria for reduced peak expiratory flow (PEF%pred < 80%), providing specific quantitative risk assessments.
- An increase in BMI is significantly related to the decreased risk of reduced peak expiratory flow, where for every unit increase in BMI there is a 3.0% decrease in the odds (OR = 0.970, 95% CI = 0.946-0.993).
- An increased hand grip strength was significantly related to the decreased risk of reduced PEF, where for every 1 kg increase in hand grip strength there is a 3.9% reduction in the risk (OR = 0.961, 95% CI = 0.952-0.970).
- Of the 8,784 total adults with no diagnosed lung disease, 671 individuals (7.64%) had reduced expiratory flow (PEF%pred < 80%).
- Mediation analysis showed that hand grip strength significantly mediates the relation between BMI and PEF%pred; however, the indirect effect size is negligible (indirect effect = 0.003; 95% CI = 0.003-0.004).
Low body mass index and decreased hand grip strength are associated independently with the higher risk of peak expiratory flow impairment among middle-aged and elderly Chinese individuals without any prior history of lung disease. The findings of this research demonstrate that even though hand grip strength is statistically significant in the mediation of the relationship between BMI and expiratory flow, the minimal effect size implies the necessity not to depend on periphery muscle strengthening alone as means of improving lung functions.
Reference:
Zhang, X., Jin, H., & Sheng, Z. (2026). Associations between body mass index and peak expiratory flow rate and the mediating role of hand grip strength: evidence from CHARLS. Clinics, 81, 101091. https://doi.org/10.1016/j.clinsp.2026.101091
