Supplementary Material for: Secondhand smoke exposure and risk of dementia in non-smokers: A population-based cohort study

Background Large population-based prospective studies are necessary to provide clarification on the associations of panoramic secondhand smoking burden, including prenatal and postnatal secondhand smoke (SHS) exposure, with the risk of developing dementia. Methods Our study comprised a sample of 353,756 dementia-free individuals from the UK Biobank who were non-smokers, had data on the exposure of maternal smoking as well as SHS exposure in daily life, which was quantified in terms of hours per week (h/wk), and whether they lived with household smokers. Multivariable Cox regression models were utilized to analyze the independent and joint associations of maternal smoking and daily life SHS exposure with dementia risk. Results During a median follow-up of 11.8 years, 4,113 participants developed dementia. Compared with those who lived in the environment without smokers, multivariable-adjusted HRs (95% CIs) were 1.11 (1.02, 1.20) and 1.31 (1.13, 1.52) for those who exposed to SHS for >0 but ≤4 h/wk and >4 h/wk, respectively, and was 1.25 (1.13, 1.39) for those who lived with smokers in the household. A positive history of maternal smoking was associated with a modestly higher risk of dementia (HR=1.07; 95% CI: 1.01, 1.15). Furthermore, compared with participants with neither history of maternal smoking nor exposure to SHS, a particularly higher risk of dementia was observed among those with both exposures (HR = 1.48; 95% CI: 1.18, 1.86). Additionally, the HR (95% CI) was 1.32 (1.10, 1.59) when comparing participants with a history of maternal smoking who lived with smokers in their households with those who had neither exposures. Conclusions Having a history of maternal smoking, longer exposure to SHS, and living with smokers in the household were each associated with an increased risk of developing dementia. Individuals who were simultaneously exposed to maternal smoking and SHS or lived with household smokers had a particularly higher dementia risk

Supplementary Material for: Potentially modifiable risk factors for dementia and mild cognitive impairment: an umbrella review and meta-analysis

Introduction The prevalence of mild and major neurocognitive disorders (NCDs), also referred to as mild cognitive impairment and dementia, is rising globally. The prevention of NCDs is a major global public health interest. We sought to synthesize the literature on potentially modifiable risk factors for NCDs. Methods We conducted an umbrella review using a systematic search across multiple databases to identify relevant systematic reviews and meta-analyses. Eligible reviews examined potentially modifiable risk factors for mild or major NCDs. We used a random effects multi-level meta-analytic approach to synthesize risk ratios for each risk factor while accounting for overlap in the reviews. We further examined risk factors for major NCD due to two common etiologies: Alzheimer’s disease and vascular dementia. Results A total of 45 reviews with 212 meta-analyses were synthesized. We identified fourteen broadly defined modifiable risk factors that were significantly associated with these disorders: alcohol consumption, body weight, depression, diabetes mellitus, diet, hypertension, less education, physical inactivity, sensory loss, sleep disturbance, smoking, social isolation, traumatic brain injury, and vitamin D deficiency. All 14 factors were associated with the risk of major NCD, and five were associated with mild NCD. We found considerably less research for vascular dementia and mild NCD. Conclusion Our review quantifies the risk associated with 14 potentially modifiable risk factors for mild and major NCDs, including several factors infrequently included in dementia action plans. Prevention strategies should consider approaches that reduce the incidence and severity of these risk factors through health promotion, identification, and early management