Social Activities and Risk of Dementia in Community-Dwelling Older People: Gender-Specific Findings From a Prospective Cohort Study.

OBJECTIVES: This study examines the gender-specific associations between a wide range of social activities and dementia risk. METHODS: A prospective cohort study was conducted involving community-dwelling older Australians (≥70 years) without significant cognitive impairment at enrolment. During the first year of enrolment, we assessed 25 self-reported social activities covering various aspects, including support from relatives and friends, community participation, social interactions with surroundings, and loneliness. Dementia diagnosis followed DSM-IV criteria, adjudicated by an international expert panel. To estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between social activities and dementia, we performed Cox proportional hazards models, adjusting for age, educational attainment, baseline global cognition, and depressive symptoms. RESULTS: Among 9,936 participants who completed all social activity questionnaires (median [IQR] age: 73.4 [71.6-77.1] years; 47.4% men), dementia was diagnosed in 3.8% of men (n = 181/4,705) and 2.6% of women (n = 138/5,231) over a median 6.4 years (IQR: 5.3-7.6, range: 0.2-10.1) follow-up. Gender-specific relationships emerged: caregiving for a person with illness/disability in women (HR: 0.65, 95% CI: 0.42-0.99), and having ≥9 relatives feeling close to call for help in men (HR: 0.56, 95% CI: 0.33-0.96; reference <9 relatives) were associated with reduced dementia risk. Unexpectedly, in women, having ≥5 friends with whom they felt comfortable discussing private matters were associated with a greater dementia risk (HR: 1.69, 95% CI: 1.10-2.59; reference ≤2 friends). Imputed models further identified that babysitting/childminding was associated with lower dementia risk in men (HR: 0.75, 95% CI: 0.56-0.99). No other social activities showed significant associations with dementia. DISCUSSION: This study provides evidence of social activities influencing dementia risk. Further investigations are required to uncover the mechanisms driving these observed relationships.

Life-space mobility and healthcare costs and utilization in older men.

OBJECTIVES: To determine the association of life-space score with subsequent healthcare costs and utilization. DESIGN: Prospective cohort study (Osteoporotic Fracture in Men [MrOS]). SETTING: Six U.S. sites. PARTICIPANTS: A total of 1555 community-dwelling men (mean age 79.3 years; 91.5% white, non-Hispanic) participating in the MrOS Year 7 (Y7) examination linked with their Medicare claims data. MEASUREMENTS: Life-space during the past month was assessed as 0 (daily restriction to one's bedroom) to 120 (daily trips outside one's town without assistance) and categorized (0-40, 41-60, 61-80, 81-100, 101-120). Total annualized direct healthcare costs and utilization were ascertained during 36 months after the Y7 examination. RESULTS: Mean total annualized costs (2020 U.S. dollars) steadily increased across category of life-space score, from $7954 (standard deviation [SD] 16,576) among men with life-space scores of 101-120 to $26,430 (SD 28,433) among men with life-space scores of 0-40 (p < 0.001). After adjustment for demographics, men with a life-space score of 0-40 versus men with a life-space score of 101-120 had greater mean total costs (cost ratio [CR] = 2.52; 95% confidence interval [CI] = 1.84-3.45) and greater risk of subsequent hospitalization (odds ratio [OR] 4.72, 95% CI 2.61-8.53) and skilled nursing facility (SNF) stay (OR 7.32, 95% CI 3.65-14.66). Life-space score was no longer significantly associated with total healthcare costs (CR for 0-40 vs 101-120 1.29; 95% CI 0.91-1.84) and hospitalization (OR 1.76, 95% CI 0.89-3.51) after simultaneous consideration of demographics, medical factors, self-reported health and function, and the frailty phenotype; the association of life-space with SNF stay remained significant (OR 2.86, 95% CI 1.26-6.49). CONCLUSION: Our results highlight the importance of function and mobility in predicting future healthcare costs and suggest the simple and convenient life-space score may in part capture risks from major geriatric domains and improve identification of older, community-dwelling men likely to require costly care.

Longitudinal Assessment of Proximal Tubular Dysfunction in HIV Seropositive and Seronegative Persons: Correlates and Implications.

BACKGROUND: Proximal tubular dysfunction (PTD) is common in HIV-positive persons and has been associated with tenofovir disoproxil fumarate (TDF). However, few studies have assessed the natural history PTD in HIV-positive and -negative individuals, or the association of PTD with the subsequent trajectory of directly measured glomerular filtration rate (mGFR). METHODS: We followed 192 HIV-positive and 100 HIV-negative, nondiabetic participants for 3 years. We measured 3 PTD markers (normoglycemic glycosuria, fractional excretion of phosphorus, and tubular proteinuria) and mGFR (by iohexol disappearance from serum) annually. We used univariate and multivariate generalized estimating equation logistic regression to identify factors associated with PTD across all visits and linear mixed effects models to assess the association between baseline PTD and mGFR slope. RESULTS: Compared with HIV-negative participants, HIV-positive persons that were not taking antiretroviral therapy were at increased risk of PTD (adjusted odds ratio 3.33; 95% confidence interval: 1.65 to 6.71), whereas those taking a TDF-based or a TDF-sparing regimen were not at significantly increased risk of PTD. Among HIV-positive participants, uncontrolled viremia was a strong correlate of PTD. Forty-nine of 55 (89%) participants with PTD at baseline had at least 1 subsequent visit without PTD. There was no association between baseline PTD and rate of decline in mGFR over time. CONCLUSIONS: Poorly controlled HIV may be a stronger risk factor for PTD than TDF use. The individual-level variability of the PTD markers over time was high, potentially limiting their usefulness for routine screening in unselected patients. Baseline PTD was not associated with subsequent mGFR slope.