Smoking and cognitive impairment among older persons in Malaysia

How Does Tobacco Use Affect the Cognition of Older Adults? A Propensity Score Matching Analysis Based on a Large-Scale Survey

INTRODUCTION

Tobacco is a well-established risk factor for cancer, but its association with other morbidities needs consideration. The low-income and middle-income countries (LMICs) with unprecedented demographic transformation lack evidence on tobacco use and its impact on cognitive health.

AIMS AND METHODS

Using a propensity score matching approach, we utilized data from the Longitudinal Ageing Study of India. Study employed 1:1 nearest neighbor matching with the replacement methodology. We estimated the odds of the poor cognitive score and tobacco use among older adults based on five different models for ever tobacco user, former tobacco user, current tobacco user, current smokers, and current smokeless tobacco users with reference to never tobacco users.

RESULTS

The estimated average treatment effect for the treated and the untreated group has shown a higher likelihood of cognitive decline among ever (OR -0.26; 95%CI -0.43 to -0.09), current (OR -0.28; 95%CI -0.45 to -0.10), and former (OR -0.53; 95%CI -0.87 to -0.19) tobacco users compared to never tobacco users. The finding further suggests the odds of lower cognitive scores among older adults who were smokers (OR -0.53; 95%CI -0.87 to -0.19) and smokeless tobacco users (OR -0.22; 95%CI -0.43 to -0.01) as compared to never tobacco users.

CONCLUSIONS

Interventions designed to prevent the incidence of cognitive impairment should focus on limiting the use of tobacco. Strategies under the tobacco-free generation initiative should be amplified in order to prevent future generations from productivity loss, premature ageing and to promote healthy aging.

IMPLICATIONS

Evidence of a definitive association between tobacco consumption and cognition among older adults is sporadic in LMICs. Though tobacco is a risk factor for various diseases including cancer, the extent of its impact on cognitive health among the older population is limited. This study contributes to the existing literature by highlighting poor cognitive outcomes among older adults who smoke tobacco and/or consume smokeless tobacco as compared to never-tobacco users. Our findings emphasize the need to accelerate programmes related to tobacco-free generation in LMICs to reach a higher quality of life and healthy aging in pursuit of achieving the sustainable development goal of "good health and well-being."

Association between cardiovascular risk factors and cognitive impairment in adults aged 60 years or older from Chile: a cross-sectional study

BACKGROUND

Few studies in Latin America have examined the association between cardiovascular risk factors and cognitive impairment (CI) in a nationally representative sample. Therefore, this study aimed to estimate the prevalence of CI in a nationally representative sample of adults aged 60 years or older from Chile and to investigate the association between cardiovascular risk factors and CI.

METHODS

Data from the cross-sectional 2016-2017 National Health Survey of Chile, which included 2031 adults (63.7% women) was used. Body mass index, metabolic syndrome (blood pressure, triglycerides, fasting glucose or treatment for diabetics, waist circumference, and HDL cholesterol), risk of cardiovascular disease (history and measured variables, using the Framingham risk score), tobacco use, and physical activity were measured. CI was assessed using the Mini-Mental Status Examination (MMSE).

RESULTS

Overall, the prevalence of CI was 12.2% at the national level. Significant differences in CI were observed by age, education level, risk of cardiovascular disease, and smoking. High risk of cardiovascular disease was associated with higher odds of CI (OR: 2.04; 95%CI: 1.20-3.45) compared to low risk. Smoking was significantly associated with a lower likelihood of CI (OR: 0.56; 95%CI: 0.36-0.87) compared to never smoking. Body mass index, metabolic syndrome, and physical activity were not associated with CI.

CONCLUSIONS

This study provided additional support for previous findings on the relationship between cognitive decline and an elevated risk of cardiovascular disease. Worse CI was associated with the group with the highest risk of cardiovascular disease, and the presence of lifestyle factors, such as obesity and physical inactivity, exacerbate this relationship, but not being a current smoker.

Mendelian randomization analyses of smoking and Alzheimer's disease in Chinese and Japanese populations

Background

Previous epidemiological studies have reported controversial results on the relationship between smoking and Alzheimer's disease (AD). Therefore, we sought to assess the association using Mendelian randomization (MR) analysis.

Methods

We used single nucleotide polymorphisms (SNPs) associated with smoking quantity (cigarettes per day, CPD) from genome-wide association studies (GWAS) of Japanese population as instrumental variables, then we performed two-sample MR analysis to investigate the association between smoking and AD in a Chinese cohort (1,000 AD cases and 500 controls) and a Japanese cohort (3,962 AD cases and 4,074 controls), respectively.

Results

Genetically higher smoking quantity showed no statistical causal association with AD risk (the inverse variance weighted (IVW) estimate in the Chinese cohort: odds ratio (OR) = 0.510, 95% confidence interval (CI) = 0.149-1.744, p = 0.284; IVW estimate in the Japanese cohort: OR = 1.170, 95% confidence interval CI = 0.790-1.734, p = 0.434).

Conclusion

This MR study, for the first time in Chinese and Japanese populations, found no significant association between smoking and AD.

The Effects of “Diet–Smoking–Gender” Three-Way Interactions on Cognitive Impairment among Chinese Older Adults

Investigations on gender variations in the risk factors of cognitive impairment are required to promote future precision medicine among older adults, as well as to contribute to a better understanding of the “male–female health-survival paradox”. With this study, we aimed to investigate the effects of “diet–smoking–gender” three-way interactions on cognitive impairments among Chinese older adults. We conducted a 16-year prospective cohort study among 15,953, 15,555, 16,849, 9716, 7116, and 13,165 older adults from the 2002, 2005, 2008–2009, 2011–2012, 2014, and 2017–2018 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), respectively. Cognitive impairment was measured by the Mini-Mental State Examination (MMSE). The dietary diversity score (DDS) was calculated using the CLHLS food frequency questionnaire. Generalized estimating equations (GEE) were used to assess the “diet–smoking–gender” three-way interaction effects on cognitive impairment across the six waves of CLHLS. We found that higher dietary diversity was associated with lower probability of cognitive impairment among older adults (OR = 0.92; 95%CI = 0.90, 0.98). However, smoking behavior may negatively influence the protective effect of higher dietary diversity on cognitive function among females (OR = 1.26; 95%CI = 1.07, 1.49). Our findings imply that we should take gender differences and lifestyle behaviors into consideration in implementing dietary interventions to improve cognitive function among older adults.

The negative impact of chronic tobacco smoking on adult neuropsychological function: a cross-sectional study

Background

The evidence on the effects of chronic tobacco smoking on neuropsychological functions is conflicting. The literature remains limited by inconsistent accounting for potentially confounding biomedical and psychiatric conditions. This study aimed to assess the neuropsychological functions of adult chronic tobacco smokers in comparison to group-matched non-smokers.

Method

The study included 73 smokers and 84 group-matched non-smokers. The data was collected during the year 2019. After an initial interview to collect demographics and smoking profile, the subjects undertook neuropsychological assessments that targeted a wide range of cognitive domains.

Results

The performance of smokers was poorer on almost all neuropsychological domains, namely selective attention (p ≤ .001, p = .044), alternating attention (p = .002) working memory (p ≤ .001), Short-term memory (p = .006 and .003), Long-term memory (p ≤ .001), processing accuracy (p ≤ .001), and executive function (p = .011 and .026). Smokers were intact on processing speed. Smoking accumulation and lower age onset of regular smoking were correlated with lower neuropsychological function.

Conclusion

Our findings add to the growing body of evidence suggesting that chronic tobacco smoking impacts cognition negatively.

A healthy diet and physical activity are important to promote healthy ageing among older Chinese people

Objective

To examine the associations between multiple health behaviours and health outcomes among older Chinese adults.

Methods

Data from the World Health Organization’s Study on global AGEing and adult health Wave 1 (2007–2010), collected among the older Chinese population, were included in this study. Smoking, diet, and physical activity were analysed by linear regression for any associations with depressive symptoms, quality of life (QoL), cognitive function, and physical function.

Results

A total of 13 367 participants aged >49 years were included in the analyses. After controlling for key socioeconomic factors, healthy diet was significantly associated with higher QoL (β = 0.099) and better cognitive function (β = 0.023). Physical activity was significantly associated with fewer depressive symptoms (β = –0.020), higher QoL (β = 0.086), better cognitive function (β = 0.072), and better physical function (β = –0.155 [higher scores = poorer physical function]). No relationship was found between smoking and any health-related outcome included in this study.

Conclusion

This study demonstrates the importance of healthy diet and physical activity for health outcomes in the older Chinese population.

Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study

BACKGROUND

With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups.

METHODS AND FINDINGS

We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54-105 (mean = 72.7) years and without dementia at baseline. Studies had 2-15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = -0.1, SE = 0.01), APOE*4 carriage (B = -0.31, SE = 0.11), depression (B = -0.11, SE = 0.06), diabetes (B = -0.23, SE = 0.10), current smoking (B = -0.20, SE = 0.08), and history of stroke (B = -0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = -0.07, SE = 0.01), APOE*4 carriage (B = -0.41, SE = 0.18), and diabetes (B = -0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = -0.24, SE = 0.12), and between diabetes and cognitive decline (B = -0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife.

CONCLUSIONS

These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.

Smoking status and cognitive performance among vocational school students in Beijing, China

INTRODUCTION

In countries where smoking is associated with lower socioeconomic status, smokers tend to perform worse on cognitive tasks than non-smokers. China is now undergoing a similar process with a recent study showing that there is a reduced cognitive performance in middle aged but not in elderly smokers. We examined the links between smoking status and cognitive functioning among vocational school students in Beijing, China.

METHODS

A total of 213 students aged 16-20 (98 smokers and 115 non-smokers) were recruited from three vocational schools in Beijing. Participants completed three subtests of Wechsler Adult Intelligence Scale (WAIS) (information, arithmetic, digit span) and Dysexecutive Questionnaire (DEX). Smokers also completed a cigarette smoking questionnaire and Fagerstrom Test of Nicotine Dependence (FTND).

RESULTS

Smokers performed worse than non-smokers in tests of arithmetic and digit span forward (t = 4.25, 2.05, both P < .05). Scores on digit span backward did not differentiate smokers and non-smokers, but among smokers, the performance on this subtest was related to the age of starting smoking (r = 0.26, p < .001). Cognitive performance in smokers was not related to tobacco dependence or intensity of smoking. Compared to non-smokers, smokers had a higher total DEX score and higher scores on three of its five subscales (Inhibition, Knowing-doing dissociation and Social regulation, all p < .05). Another subscale, In-resistance, did not differentiate smokers and non-smokers, but differentiated smokers with lower and higher levels of nicotine dependence (t = -2.12, p < .05).

CONCLUSION

Smokers performed worse on some cognitive tasks than non-smokers and scored higher on a questionnaire assessing executive dysfunction.

Major health impact of accelerated aging in young HIV-infected individuals on antiretroviral therapy

BACKGROUND

Aging among HIV-infected individuals on antiretroviral therapy (ART) is a significant clinical challenge; however, studies assessing multidimensional aspects of aging are lacking. We characterized 10 geriatric conditions encompassing multiple functional domains, its health impact and associated risk factors in HIV-infected and age-matched uninfected controls.

METHODS

HIV-infected individuals were recruited from the outpatient clinic in University Malaya Medical Centre, Malaysia and controls from the community. All participants were aged at least 25 years of age with no acute illness, and HIV-infected individuals were on stable ART. Geriatric conditions were assessed and the burden scored as a composite of geriatric conditions present in an individual (total score = 10). Multivariate regression analysis was performed to determine the risk factors and health impact associated with the burden of geriatric conditions.

RESULTS

We analyzed data from 336 HIV-infected individuals (total HIV+), of whom 172 were matched for age, sex, and ethnicity with 172 HIV-uninfected controls (matched subset). In the total HIV-positive cohort, median (interquartile range) age was 44 (38-51) years and CD4 T-cell count was 562 (398-737) cells/μl. The burden of geriatric conditions was significantly higher in the HIV-infected group compared with controls (P < 0.001). With an increasing geriatric condition burden, quality-of-life scores were 2.2-times poorer, healthcare use five times greater, and mortality risk scores four times higher in the HIV-infected group compared with matched controls. Both sociobehavioural and HIV-related clinical factors were independently associated with an increasing burden of geriatric condition in HIV.

CONCLUSIONS

A high burden of geriatric conditions with significant impact on health outcomes, including mortality risk scores are observed among HIV-infected individuals on ART in a resource-limited setting.

Association between current smoking and cognitive impairment depends on age: A cross-sectional study in Xi'an, China

BACKGROUND

Cigarette smoking is a modifiable risk factor for cognitive impairment, while the relationship between current smoking and cognitive impairment is not fully understood. The objectives were to identify a possible association between current smoking and cognitive impairment depending on age in the Chinese rural population.

METHODS

Data for the study consisted of 1,782 participants (40 years and older) who lived in a rural village in the vicinity of Xi'an, China. Data about smoking history and cognitive function were collected. Cognitive function was scored by the Mini-Mental State Examination. The effect of age on the relationship between current smoking and cognitive impairment was analyzed with interaction and stratified analysis by logistic regression models.

RESULTS

Interaction analysis showed that current smoking is positively related with cognitive impairment (odds ratio [OR]=9.067; 95% confidence interval [95% CI] 1.305-62.979; P=.026). However, the interaction term, age by current smoking, is negatively related with cognitive impairment (OR=0.969; 95%CI 0.939-0.999; P=.045). Stratified logistic regression showed that in the 40-65 years of age sublayer, OR of current smoking is 1.966 (P=.044), whereas in the>65 years of age sublayer, the OR is 0.470 (P=.130). This means that the association between current smoking and cognitive impairment with age might be positive (OR>1) in lower age sublayers, but no significant difference in higher age sublayers.

CONCLUSIONS

In conclusion, current smoking might be positively associated with cognitive impairment in the middle-aged but the relationship declines with increasing age.