A Dyadic Growth Modeling Approach to Examine Associations Between Weight Gain and Lung Function Decline: The NHLBI Pooled Cohorts Study.

The relationship between body weight and lung function is complex. Using a dyadic multilevel linear modeling approach, treating body mass index (BMI) and lung function as paired, within-person outcomes, we test the hypothesis that individuals with more rapid increase in BMI exhibit more rapid decline in lung function: forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and their ratio (FEV1/FVC). Models included random intercepts and slopes and were adjusted for socio-demographic and smoking-related factors. A sample of 9,115 adults with paired measurements of BMI and lung function at >/=3 visits were selected from a pooled set of 5 US population-based cohorts (1983 - 2018; mean age at baseline, 46 years; median follow-up, 19 years). At age 46, average annual rates-of-change in BMI, FEV1, FVC, and FEV1/FVC were 0.22 kg/m2/year, -25.50 mL/year, -21.99 mL/year, and -0.24 percent/year, respectively. Individuals with steeper BMI increases had faster declines in FEV1 (r=-0.16) and FVC (r=-0.26), and slower declines in FEV1/FVC (r=0.11) (all P<0.0001). Results were similar in subgroup analyses. Residual correlations were negative (P<.0001), suggesting additional interdependence between BMI and lung function. Results show that greater rates of weight gain are associated with greater rates of lung function loss.