# The COPD risk associated with adulthood weight change and early adulthood BMI: a prospective cohort study

## TL;DR

The study found that weight changes and early adulthood BMI are linked to COPD risk, with different patterns in males and females.

## Contribution

The study reveals sex-specific associations between weight changes and early BMI with COPD risk using a large prospective cohort.

## Key findings

- In males, higher early adulthood BMI and weight gain were inversely associated with COPD risk.
- Early adulthood obesity increased COPD risk in males, especially non-current smokers.
- In females, extreme weight loss or gain in adulthood increased COPD risk, particularly in underweight or obese early adulthood groups.

## Abstract

Gaps concerning general adiposity and chronic obstructive pulmonary disease (COPD) are delaying policies for weight interventions in COPD prevention, especially adiposity in early adulthood and weight changes during adulthood.

Based on the China Kadoorie Biobank, a prospective cohort between 2004–2008 covering 5 urban and 5 rural areas, we included 138,764 males and 194,159 females aged 35 ~ 70 years. Weight change was defined as the difference between directly measured weight at baseline and self-reported weight at age 25. Incident COPD events were followed-up until the end of 2018. Cox proportional hazard models were conducted to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of adulthood weight change and early adulthood body mass index (BMI) with COPD risk.

During a mean follow-up of 11.9 years, 3,732 and 3,154 incident COPD events occurred in males and females, respectively. In males, weight change and early adulthood BMI were inversely associated with COPD risk, while early adulthood obesity (BMI ≥ 28.0 kg/m2) was associated with an increased risk of COPD (HR = 1.76; 95% CI: 1.01, 3.08), compared with the 18.5 ~ 23.9 kg/m2 early adulthood BMI group, among non-current smokers. In females, extreme weight loss and gain were associated with increased COPD risk. The effects of weight loss and gain on COPD were enhanced in the underweight and obese population, respectively, in early adulthood.

Weight change and early adulthood BMI were inversely linked to COPD risk in males, while in females, both extreme weight loss or gain increased COPD risk.

The online version contains supplementary material available at 10.1186/s12889-025-25582-z.