Smoking and Obesity as Risk Factors in Frontotemporal Dementia and Alzheimer's Disease: The HUNT Study

BACKGROUND: Few studies have assessed smoking and obesity together as risk factors for frontotemporal dementia (FTD) and Alzheimer's disease (AD). OBJECTIVE: To study smoking and obesity as risk factors for FTD and AD. METHODS: Ninety patients with FTD and 654 patients with AD were compared with 116 cognitively healthy elderly individuals in a longitudinal design with 15–31 years between measurements of risk factors before the dementia diagnosis. RESULTS: There were no associations between smoking and FTD (p = 0.218; odds ratio [OR]: 0.990; 95% confidence interval [CI]: 0.975–1.006). There were significant associations between obesity and FTD (p = 0.049; OR: 2.629; 95% CI: 1.003–6.894). There were significant associations between both smoking (p = 0.014; OR: 0.987; 95% CI: 0.977–0.997) and obesity (p = 0.015; OR: 2.679; 95% CI: 1.211–5.928) and AD. CONCLUSION: Our findings suggest that obesity is a shared risk factor for FTD and AD, while smoking plays various roles as a risk factor for FTD and AD.