*3.6. HHIP Serum Levels*

The serum HHIP protein levels were determined through ELISA assays in 80 randomly selected women exposed to burning biomass smoke (COPD-BS = 40 and BBES = 40) (Supplementary Table S2); these subgroups were derived from the main groups. COPD patients had a median age of 71.5 years, while in women without the disease, the mean age was 64 years (*p* = 0.003); for this reason, age, and BMI, were employed as a covariables to adjust.
