Multilingualism and Dementia Risk: Longitudinal Analysis of the Nun Study.

BACKGROUND: Multilingualism is associated with enhanced executive function and may thus prevent cognitive decline and reduce the risk of dementia. OBJECTIVE: To determine whether multilingualism is associated with delayed onset or reduced risk of dementia. METHODS: Dementia was diagnosed in the Nun Study, a longitudinal study of religious sisters aged 75+ years. Multilingualism was self-reported. Dementia likelihood was determined in 325 participants using discrete-time survival analysis; sensitivity analyses (n = 106) incorporated additional linguistic measures (idea density and grammatical complexity). RESULTS: Multilingualism did not delay the onset of dementia. However, participants speaking four or more languages (but not two or three) were significantly less likely to develop dementia than monolinguals (OR = 0.13; 95% CI = 0.01, 0.65, adjusted for age, apolipoprotein E, and transition period). This significant protective effect of speaking four or more languages weakened (OR = 0.53; 95% CI = 0.06, 4.91) in the presence of idea density in models adjusted for education and apolipoprotein E. CONCLUSION: Linguistic ability broadly was a significant predictor of dementia, although it was written linguistic ability (specifically idea density) rather than multilingualism that was the strongest predictor. The impact of language on dementia may extend beyond number of languages spoken to encompass other indicators of linguistic ability. Further research to identify the characteristics of multilingualism most salient for risk of dementia could clarify the value, target audience, and design of interventions to promote multilingualism and other linguistic training as a strategy to reduce the risk of dementia and its individual and societal impacts.

The relationship between adiposity and gleason score in men with localized prostate cancer.

BACKGROUND: We investigated the relationship between body mass index (BMI) at the time of cancer diagnosis and malignant phenotype as measured by Gleason score. METHODS: This was a population-based cross-sectional study conducted on 1,096 prostate cancer patients treated for cure in Ontario, Canada between 1990 and 1998. An electronic-linked data set was enhanced by retrospective chart review. BMI was categorized as: normal (BMI <25.0), overweight (BMI 25.0-29.9), and obese (BMI ≥30). We also investigated the role of diabetic status. Gleason scores were categorized as: 2-4, 5-6, 7, and 8-10. We assessed the effect modification by patient age. RESULTS: BMI was not associated with Gleason score; 9.7% of those with normal BMI had a Gleason score ≥8, and 9.4% fell into this Gleason category in both the overweight and obese groups (P = 0.73). 11.7% of diabetics had a Gleason score ≥8 compared to 9.3% in the non-diabetic group (P = 0.79). Both of these results persisted in a multivariate analysis controlling for age and diagnosis year. When stratified by age, only the Gleason score distribution in the youngest cohort (50- to 59-year olds) indicated higher Gleason scores in the obese group, with marginally significant results (P = 0.16). CONCLUSIONS: With a possible exception in younger men, elevated BMI at the time of diagnosis does not appear to be associated with aspects of aggressive behavior associated with Gleason grade. The effect of adiposity on prostate cancer outcome is complex, requiring further study that includes attention to factors such as length of exposure, concomitant co-morbidities, and ethnicity.