Childhood Secondhand Smoke Exposure and Risk of Dementia in Adulthood

I read the paper by Zhou et al. with great interest (1). The authors conducted a long-term follow-up study to investigate the associations between exposure to secondhand smoke and the subsequent risk of dementia, Alzheimer's disease (AD), and stroke (1). The adjusted hazard ratios (HRs; 95% confidence intervals [CIs]) of the highest exposure to secondhand smoke compared to individuals with no exposure for dementia, AD, and stroke were 2.86 (2.00–4.09), 3.13 (1.80–5.42), and 1.89 (1.37–2.61), respectively. In addition, a dose–response relationship was also observed in this study. I would like to present some information relevant to their study.