Associations Of Pulmonary Function And Muscular Strength With Metabolic Syndrome In Lung Healthy Older Adults

PURPOSE: Low pulmonary function (PF) is associated with prevalent metabolic syndrome (MetS), while muscular strength (MS) is inversely associated with MetS. However, the independent and joint associations of PF and MS with MetS in lung healthy older adults is unclear. METHODS: This study consisted of 363 older adults aged 65-95 years (63% female), free from cardiovascular and lung disease. PF and MS were evaluated by spirometry and a handheld dynamometer, respectively, and categorized into tertiles (upper, middle, and lower) for each. MetS was defined as having ≥3 of the following: abdominal obesity, high triglycerides, low HDL, high blood pressure, and/or high glucose. The odds ratios (ORs) and 95% confidence intervals (CIs) of MetS across tertiles of PF and MS were calculated using logistic regression, adjusting for age, sex, smoking status, heavy alcohol drinking, and cardiorespiratory fitness. Four groups were created using the upper two thirds (high) and lower one third (low) of the MS and PF distributions to explore joint associations: ‘high MS/high PF’, ‘high MS/low PF’, ‘low MS/high PF’, and ‘low MS/low PF’. RESULTS: There were 120 (33%) cases of MetS. Compared to those in the upper PF tertile, the ORs (95% CIs) of MetS in the middle and lower tertiles were 1.59 (0.86-2.92) and 1.74 (0.95-3.19), respectively, after adjusting for confounders, including MS (P trend = 0.08). Compared to the upper MS tertile, the ORs (95% CIs) of MetS in the middle and lower tertiles were 2.97 (1.53-5.74) and 6.00 (2.90-12.12), respectively, after adjusting for confounders, including PF (P trend <0.01). Compared to ‘high MS/high PF,’ the ORs (95% CIs) of MetS for ‘high MS/low PF’, ‘low MS/high PF’, and ‘low MS/low PF’ were 1.17 (0.60-2.28), 2.82 (1.48-5.35), and 4.13 (2.07-8.24), respectively, after adjusting for confounders. CONCLUSIONS: The association between MS and MetS is independent of PF, and the prevalence of MetS is greatest among those with low MS, regardless of PF.