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Background: Olfactory impairment is associated with dementia in clinical settings. We examined the relationship of olfactory identification function with all‐cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD) and assessed the discriminative ability of the Sniffin' Sticks Identification Test (SSIT), the self‐rated Ascertain Dementia 8‐item Questionnaire (AD8), and their combination for dementia detection among rural‐dwelling older adults in China. Methods: This population‐based cross‐sectional study included 4481 participants (age ≥ 65 years; 56.8% women; 38.1% illiteracy) living in rural communities. The 16‐item SSIT was performed to assess olfactory identification function. The self‐rated AD8 was administered to participants for cognitive status. We diagnosed dementia, AD, and VaD following the international criteria. Data were analyzed with logistic regression models and receiver operating characteristic curve. Results: Of the 4481 participants, dementia was diagnosed in 139 persons (3.1%), including 92 with AD and 42 with VaD. The SSIT score (range, 0–16) was associated with multiadjusted odds ratios of 0.83 (95% CI: 0.79–0.88) for dementia, 0.84 (0.79–0.90) for AD, and 0.79 (0.71–0.87) for VaD. The area under the curve for the discrimination between participants with and without dementia was 0.73 (95% CI: 0.69–0.77) for SSIT score ≤ 8 alone, 0.86 (0.82–0.89) for self‐rated AD8 score ≥ 3 alone, and 0.89 (0.86–0.92) for their combination using a logistic model. Conclusions: Olfactory impairment is a clinical marker for all‐cause dementia, AD, and VaD. The smell identification test, in combination with the brief self‐rated cognitive screening tool, is accurate for screening dementia among rural‐dwelling Chinese older adults with no or limited education. [ABSTRACT FROM AUTHOR]

The cross-sectional association between late-life obesity and dementia is often explained by the obesity paradox. We assessed the potential differential associations of various adiposity indices with dementia and subtypes of dementia in rural Chinese older adults. A population-based cross-sectional study. A total of 5277 participants (age ≥60 years; 57.23% female) who were living in rural communities and were examined in March–September 2018 for MIND-China. We used weight, height, and waist circumference (WC) to calculate 6 adiposity indices: body mass index (BMI), waist-to-height ratio (WHtR), weight-adjusted-waist index (WWI), A Body Shape Index (ABSI), body roundness index (BRI), and Conicity Index (ConI). Dementia, Alzheimer's disease (AD), and vascular dementia (VaD) were clinically diagnosed following the international criteria. Data were analyzed with logistic regression models. Of the 5277 participants, 303 were diagnosed with dementia, including 193 with AD and 99 with VaD. The multivariable-adjusted odds ratio (95% CI) of dementia associated with the highest (vs lowest) quintile of adiposity index was 2.32 (1.40–3.85) for WWI, 1.56 (1.03–2.36) for ABSI, and 1.40 (0.92–2.11) for ConI. Similarly, higher levels of these 3 adiposity indices were significantly associated with an increased likelihood of AD, whereas a higher BMI was associated with a decreased likelihood of AD. None of the 6 examined adiposity indices was significantly associated with VaD when adjusting for multiple confounders. The adiposity index WWI is linearly associated with the likelihood of dementia and AD. An increased WWI may be a clinical marker for the dementia syndrome and Alzheimer's dementia. [ABSTRACT FROM AUTHOR]