Occupational risk factors for early onset dementia (EOD) in the Modena population: a case-control study

Introduction Dementia is a clinical condition generally affecting subjects in the elderly. However, it may occur also at younger age, yielding a condition called early-onset dementia (EOD) characterized by an onset before 65 years 1 2. Despite the limited epidemiological data and the paucity of information regarding possible risk fac- tors 3 4, there is a general agreement that clinical presentation and consequences on daily life are different than late-onset demen- tia, due to the occurrence when subjects are still involved within occupational activities as well as familiar responsibilities 5. The aim of this work is to assess the epidemiological, clinical and prognostic role of occupational risk factors in EOD. Materials and methods Using a case-control design, we recruited newly-diagnosed EOD cases from the two Centers of Cognitive Disease of the Neurol- ogy Units of Modena-Baggiovara and Carpi Hospitals, as well as from the community health centers and general practitioners, October 1, 2016 to May 31, 2019. Referent population have been recruited from care-givers of EOD and LOD (late onset demen- tia) subjects. We investigated as possible risk factors of the dis- ease the occupational history, by administering a questionnaire collecting information about personal characteristics, family his- tory of diseases, clinical history and comorbidities, occupation activities, hobbies and other leisure activities, residential history, domestic use of pesticides, and dental care. We computed the odds ratios (ORs) of EOD risk, and the corresponding 95% con- fidence intervals (CIs), according to exposure to the investigated risk factors using an unconditional logistic regression model ad- justing for sex, age, and educational attainment. Results Fifty-six cases and fifty-three controls agreed to participate, with generally higher number of women (60% cases and 55% controls) and people over 65 (60% cases compared to 49% con- trols). About occupational factors, working in the agricultural sector seemed to be only slightly associated with risk of EOD (OR 1.31, 95% CI 0.26-6.59), while an increased risk was found for industrial sector (OR 2.23, 95% CI 0.85-5.88). Occupational exposure to contaminants showed positive association for occupational exposure to selenium (OR 2.23, 95% CI 0.11-46.42), aluminum (OR 2.75, 95% CI 0.42-18.11), pesticides (OR 2.10, 95% CI 0.60-7.36), dyes, paints or thinners (OR 2.07, 95% CI 0.70-6.05), while no association was found for exposure to or use of electric and electronic system or electromagnetic fields. Conclusions Results of this study suggest that some occupational factors, namely use of pesticides, dyes/paints, and metalloids such as alu- minum and selenium, could be associated with increased disease risk. Despite study limitations due to case-control design, includ- ing possible occurrence of selection and recall bias, our findings support the hypothesis of an environmental etiology of EOD.