Metabolic Health, Overweight or Obesity, and Lung Function in Older Australian Adults

Background: Few studies have explored the links between adiposity, metabolic health, and lung function. This study examined the cross-sectional association between spirometric lung function and overweight/obesity, with and without metabolic abnormalities, in older adults. Methods: The research involved 3,318 older adults from the Hunter Community Study Cohort who had a BMI of 18.5 kg/m² or higher. Participants were grouped based on BMI and metabolic health risk. Obesity was defined as a BMI of 30 kg/m² or more, while metabolic health was determined by the absence of risk factors according to the International Diabetes Federation criteria. Lung function was assessed via spirometry, measuring FEV1, FVC, predicted FEV1, predicted FVC, and FEV1/FVC ratio. Lung dysfunction was classified into restrictive, obstructive, mixed patterns, and deviations from predicted FEV1 and FVC. Results: The mean lung function measurements were as follows: FEV1 2.4 L (0.7), FVC 2.9 L (0.8), predicted FEV1% 88.7% (17.6), predicted FVC% 85.6% (15.7), and FEV1/FVC 82.5% (8.5). Compared to the metabolically healthy normal weight (MHNW) group, the odds of lung dysfunction were as follows. For the restrictive pattern, the MHOW group had an odds ratio (OR) of 1.00 (95% CI: 0.70-1.47, p = 0.959) and the MHO group had an OR of 1.67 (95% CI: 1.13-2.49, p = 0.011). For the obstructive pattern, the MHOW group had an OR of 0.39 (95% CI: 0.20-0.77, p = 0.007) and the MHO group had an OR of 0.36 (95% CI: 0.12-1.05, p = 0.061). For the mixed pattern, the MHOW group had an OR of 0.39 (95% CI: 0.18-0.87, p = 0.021) and the MHO group had an OR of 0.29 (95% CI: 0.10-0.87, p = 0.027). Conclusions: A higher BMI and variations in metabolic health are associated with an increased likelihood of restrictive lung function patterns. Conversely, obesity is inversely related to obstructive lung function patterns.