| Objective: Currently,accumulated evidence has shown that several potentially modifiable lifestyle factors are related to cognitive health,including smoking,alcohol drinking,dietary patterns and sleep duration.However,these results are inconsistent due to the differences in study design,sample size,and adjustment for confounding factors.In addition,most of these studies have been conducted in Western populations,and evidence from Chinese populations is limited.In this study,we aimed to evaluate the relations of lifestyle factors(smoking,alcohol drinking,dietary patterns and sleep duration and change in sleep duration)in midlife with risk of cognitive impairment of elderly adults based on a prospective cohort study with a large sample size and long follow-up duration,aiming at providing key scientific evidence for the prevention and control of cognitive disorders in the Chinese population.Methods: We used data from 16948 men and women,who had been followed-up for mean of 20 years as participants of the Singapore Chinese Health Study.Data on smoking,alcohol drinking and diet intake were collected at baseline(1993–1998),when participants were aged 45–74(mean 53)years.Diet quality at baseline was assessed according to the alternate Mediterranean diet(a MED),the Dietary Approaches to Stop Hypertension(DASH)diet,Alternative Healthy Eating Index(AHEI)-2010,Plant-based Diet Index(PDI)and healthful Plant-based Diet Index(h PDI).Daily sleep duration was assessed at baseline(1993-1998)and follow-up 2(2006-2010)interviews.Cognitive function was evaluated with a Singapore-modified Mini-Mental State Examination(SM-MMSE)during follow-up 3 visits(2014–2016),when participants were aged 61–96(mean 73)years.Multivariable logistic regression models were used to estimate the odds ratios(ORs)and 95% confidence intervals(CIs)for risk of cognitive impairment.We also used generalized linear models to compare mean SM-MMSE scores of lifestyle factors with adjustment for aforementioned covariates.To test the robustness of our findings,we have conducted a series of stratified analyses and sensitivity analyses.Result: Of 16948 participants,14.4% were defined as cognitive impairment.Compared with non-current smokers,current smokers had 20% higher risk of cognitive impairment(OR=1.20,95% CI=1.04–1.39).Compared with those who drank less than weekly,regular alcohol drinking(at least weekly)had a 17% increased risk(OR=1.17,95% CI=1.01–1.36).Compared with those who were neither smokers nor drinkers,those who were either current smokers or regular drinkers alone had no significantly increased risk,while the risk was highest for those who were both current smokers and regular drinkers(OR=1.77,95% CI=1.39–2.26,P for interaction = 0.003)The OR(95% CI)for cognitive impairment comparing the highest with the lowest quartile of diet quality scores was 0.67(0.59-0.77)for a MED,0.71(0.62-0.81)for DASH,0.75(0.66-0.85)for AHEI-2010,0.82(0.71-0.94)for PDI,and 0.78(0.68-0.90)for h PDI(all Ptrend<0.001).Each standard deviation increment in different diet quality scores was associated with 7%-16% lower risk of cognitive impairment.In the generalized linear models,the adjusted mean SM-MMSE scores were higher with increasing quartiles of five dietary scores(all P-trend <0.001).The differences of the adjusted mean scores between the highest and the lowest quartiles were equivalent to differences observed among participants 2.93 years younger in age for a MED,2.72 years younger for DASH,2.45 years younger for AHEI-2010,1.76 years younger for PDI,and 1.89 years younger for h PDI.We found a U-shaped relationship between sleep duration and risk of cognitive impairment,and the adjusted ORs(95% CIs)for cognitive impairment were 1.15(0.97-1.36)for ≤5 h/day,1.12(0.99-1.26)for 6 h/day,1.15(1.02-1.29)for 8 h/day and 1.15(0.94-1.41)for ≥9 h/day compared with recommended sleep duration at baseline.Compared with recommended sleep duration at both baseline and follow-up 2,maintaining long sleep duration(1.50,1.04-2.16),prolonging sleep duration from short(2.18,1.37-3.45)or recommended(1.55,1.20-2.02)to long,shortening sleep duration from long to short(2.93,1.35-6.34)were associated with increased risk of cognitive impairment.Conclusions: In conclusion,co-existence of smoking and regular alcohol drinking at midlife had a much stronger impact than the individual factors on risk of cognitive impairment in late life.Our study provides evidence that adherence to healthy dietary patterns in midlife is associated with a lower risk of cognitive impairment in late life.short or long sleep or adverse changes in sleep duration were associated with higher risk of cognitive impairment.Our findings indicate that maintaining recommended sleep duration is critical for the prevention of cognitive impairment. |
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