Sex Differences in the Association Between Body Mass Index and Dementia Risk in Community-Dwelling Japanese People Aged 40-74 Years.

BACKGROUND: The association between body mass index (BMI) and dementia risk is heterogeneous across age groups and might be influenced by sex. OBJECTIVE: This study aimed to clarify sex differences in the association between BMI and dementia risk in community-dwelling people. METHODS: This cohort study with an 8-year follow-up targeted 13,802 participants aged 40-74 years at baseline in 2011-2013. A self-administered questionnaire requested information on body size, including height, weight, and waist circumference (the values of which were validated by direct measurement), socio-demographics, lifestyle, and disease history. BMI was calculated and categorized as < 18.5 (underweight), 18.5-20.6 (low-normal), 20.7-22.6 (mid-normal), 22.7-24.9 (high-normal), 25.0-29.9 (overweight), and≥30.0 kg/m2 (obese). Incident cases of dementia were obtained from the long-term care insurance database. A Cox proportional hazards model was used to calculate multivariable-adjusted hazard ratios (HRs). RESULTS: The mean age of participants was 59.0 years. In men, higher BMI was associated with lower dementia risk (fully-adjusted p for trend = 0.0086). In women, the association between BMI and dementia risk was U-shaped; the "underweight," "low-normal," and "overweight" groups had a significantly higher risk (fully-adjusted HR = 2.12, 2.08, and 1.78, respectively) than the reference ("high-normal" group). These findings did not change after excluding dementia cases which occurred within the first four years of the follow-up period. CONCLUSION: Overweight/obese women, but not men, had an increased risk of dementia, suggesting that sex differences in adiposity might be involved in the development of dementia.

A neo-functionalized homolog of host transmembrane protein controls localization of bacterial endosymbionts in the trypanosomatid Novymonas esmeraldas.

The stability of endosymbiotic associations between eukaryotes and bacteria depends on a reliable mechanism ensuring vertical inheritance of the latter. Here, we demonstrate that a host-encoded protein, located at the interface between the endoplasmic reticulum of the trypanosomatid Novymonas esmeraldas and its endosymbiotic bacterium Ca. Pandoraea novymonadis, regulates such a process. This protein, named TMP18e, is a product of duplication and neo-functionalization of the ubiquitous transmembrane protein 18 (TMEM18). Its expression level is increased at the proliferative stage of the host life cycle correlating with the confinement of bacteria to the nuclear vicinity. This is important for the proper segregation of bacteria into the daughter host cells as evidenced from the TMP18e ablation, which disrupts the nucleus-endosymbiont association and leads to greater variability of bacterial cell numbers, including an elevated proportion of aposymbiotic cells. Thus, we conclude that TMP18e is necessary for the reliable vertical inheritance of endosymbionts.

Association between Sarcopenia and Depressive Symptoms in Community-Dwelling People Aged 40 Years and Older.

Several studies have reported an association between sarcopenia and depression. Their results, however, are inconsistent, partly due to small sample sizes and lack of consideration of important confounders. The present study aimed to cross-sectionally examine this association in community-dwelling people in Japan. This study used baseline data from the Yuzawa cohort study (age ≥ 40 years), with the final analysis population comprising 2,466 participants. A self-administered questionnaire was used to elicit information related to sarcopenia, depressive symptoms, demographic characteristics, anthropometrics, disease history, and lifestyles. Sarcopenia was diagnosed using SARC-F, a validated questionnaire including components of Strength, Assistance in walking, Rising from a chair, Climbing stairs, and Falls. Depressive symptoms were assessed using the 11-item version of the Center for Epidemiologic Studies Depression Scale (CES-D). For depressive symptoms, prevalence ratios (PRs) were calculated, and odds ratio (ORs) were obtained using simple and multiple logistic regression analyses. Mean age of participants was 61.7 years (standard deviation = 11.8), and 10.5% and 34.7% had sarcopenia and depressive symptoms, respectively. Sarcopenic individuals had a significantly higher PR (2.00), unadjusted OR (3.67), and adjusted OR (4.96) compared to non-sarcopenic individuals, with an estimated adjusted PR of 2.7. There was a significant dose-dependent association between SARC-F scores and depressive symptoms in sarcopenic individuals (adjusted P for trend = 0.0028). In conclusion, sarcopenia and depressive symptoms were robustly associated in community-dwelling, middle-aged and older people in Japan. However, the direction of this association is unclear, and a future cohort study will be needed to determine causality.