Prior research indicates that neighbourhood disadvantage increases dementia risk. There is, however, inconclusive evidence on the relationship between nativity and cognitive impairment. To our knowledge, our study is the first to analyse how nativity and neighbourhood interact to influence dementia risk.

Ten years of prospective cohort data (2011–2020) were retrieved from the National Health and Aging Trends Study, a nationally representative sample of 5,362 U.S. older adults aged 65+. Cox regression analysed time to dementia diagnosis using nativity status (foreign- or native-born) and composite scores for neighbourhood physical disorder (litter, graffiti and vacancies) and social cohesion (know, help and trust each other), after applying sampling weights and imputing missing data.

In a weighted sample representing 26.9 million older adults, about 9.5% (n = 2.5 million) identified as foreign-born and 24.4% (n = 6.5 million) had an incident dementia diagnosis. Average baseline neighbourhood physical disorder was 0.19 (range 0–9), and baseline social cohesion was 4.28 (range 0–6). Baseline neighbourhood physical disorder was significantly higher among foreign-born (mean = 0.28) compared to native-born (mean = 0.18) older adults (t = −2.4, p = .02). Baseline neighbourhood social cohesion was significantly lower for foreign-born (mean = 3.57) compared to native-born (mean = 4.33) older adults (t = 5.5, p < .001). After adjusting for sociodemographic, health and neighbourhood variables, foreign-born older adults had a 51% significantly higher dementia risk (adjusted hazard ratio = 1.51, 95% CI = 1.19–1.90, p < .01). There were no significant interactions for nativity with neighbourhood physical disorder or social cohesion.

Our findings suggest that foreign-born older adults have higher neighbourhood physical disorder and lower social cohesion compared to native-born older adults. Despite the higher dementia risk, we observed for foreign-born older adults, and this relationship was not moderated by either neighbourhood physical disorder or social cohesion. Further research is needed to understand what factors are contributing to elevated dementia risk among foreign-born older adults.

We determined the association between neighborhood socio-environmental factors and insomnia symptoms in a nationally representative sample of US adults aged >50 years.

Data were analyzed from two waves (2006 and 2010) of the Health and Retirement Study using 7,231 community-dwelling participants (3,054 men and 4,177 women) in the United States. Primary predictors were neighborhood physical disorder (e.g. vandalism/graffiti, feeling safe alone after dark, and cleanliness) and social cohesion (e.g. friendliness of people, availability of help when needed, etc.); outcomes were insomnia symptoms (trouble falling asleep, night awakenings, waking too early, and feeling unrested).

After adjustment for age, income, race, education, sex, chronic diseases, body mass index, depressive symptoms, smoking, and alcohol consumption, each one-unit increase in neighborhood physical disorder was associated with a greater odds of trouble falling asleep (odds ratio (OR) = 1.09, 95% confidence interval (CI): 1.04–1.14), waking too early (OR = 1.05, 95% CI: 1.00–1.10), and, in adults aged ≥69 years (adjusting for all variables above except age), feeling unrested in the morning (OR = 1.11, 95% CI: 1.02–1.22 in 2006). Each one-unit increase in lower social cohesion was associated with a greater odds of trouble falling asleep (OR = 1.06, 95% CI: 1.01–1.11) and feeling unrested (OR = 1.09, 95% CI: 1.04–1.15).

Neighborhood-level factors of physical disorder and social cohesion are associated with insomnia symptoms in middle-aged and older adults. Neighborhood-level factors may affect sleep, and consequently health, in our aging population.