Fish consumption and dementia in older people: impacts and determinants

A thesis submitted in partial fulfilment of the requirement of the University of Wolverhampton for the Degree of Doctor of Philosophy.Background: Dementia is one of the world's biggest health problems and is a major public health challenge that is becoming more common as the aged population grows. There is no known cure for dementia, and thus more efforts have been made to investigate its risk or protective factors for prevention. Previous studies suggested that increased consumption of fish reduces the risk of cardiovascular diseases. However, it is unclear whether the consumption of fish was associated with the risk of dementia and outcomes of people with dementia. Also, few studies have specifically examined factors influencing the consumption of fish in older people, despite the world population aging. The purpose of this research project was to conduct a systematic literature review and examine the determinants and impacts of fish consumption on the incidence and mortality of dementia in older people using a convergent parallel database mixed methodological approach. Methods: This study employed a systematic literature review and a mixed method of quantitative and qualitative approaches that is based on a large cohort study dataset from China and two focus group discussions from the United Kingdom. In 2007-2009, 6071 participants aged ≥60 years were randomly selected from urban and rural communities in five-provinces, China. Using a standard interview method, participants’ socio-economic status, disease risk factors and fish consumption over the past two years were documented at baseline and this was followed up until 2012. The data of the cohort were analysed in multivariate adjusted logistic regression and Cox proportional hazards regression models. In 2018, the focus group discussions that consisted of 12 older adults were conducted in the UK, and the qualitative data was analysed using thematic analysis. Results: The findings of these studies demonstrated that increased consumption of fish was associated with reduced risk of dementia and all-cause mortality among older people. The study also examined and found that large socioeconomic inequalities, and certain lifestyle, psychosocial factors and health-related conditions are significant determinants of fish consumption. The qualitative study further revealed that participants consume fish for its taste, flavour, the desire for variety of food and the nutritional and health benefit including reducing the risk of dementia and other health outcomes. Although cost, bony/scaly fish, smell and availability/accessibility of fish were highlighted as the major barriers of fish consumption. Conclusions: This research has provided evidence for preventing dementia and reducing all-cause mortality through adequate fish consumption. The findings of the study should be extended to improve public health policy, and this could form the basis for further research

Impact of fish consumption on all-cause mortality in older people with and without dementia: a community-based cohort study

BACKGROUND Increased fish consumption reduces the risk of dementia. However, it is unknown whether fish consumption reduced all-cause mortality in people with dementia. The purpose of the study is to investigate the association of fish consumption with all-cause mortality in older people with dementia versus those without dementia. METHODS Using a standard method of the Geriatric Mental State, we interviewed 4165 participants aged ≥ 60 years who were randomly recruited from five provinces in China during 2007-2009 to collect the baseline data of socio-demography, disease risk factors, histories of disease, and details of dietary intakes, and diagnosed dementia (n = 406). They were followed up for vital status until 2012. RESULTS The cohort follow-up documented 329 deaths; 61 were in participants with dementia (55.3 per 1000 person-years) and 224 were those without dementia (22.3). In all participants, the risk of all-cause mortality was reduced with fish intake at " ≥ twice a week" (multivariate-adjusted hazard ratio 0.58, 95% CI 0.34-0.96) and at "once a week or less" (0.79, 0.53-1.18) compared to "never eat" over the past two years. In participants without baseline dementia, the corresponding HRs for all-cause mortality were 0.57 (0.33-0.98) and 0.85 (0.55-1.31), while in participants with dementia were 1.36 (0.28-6.60) and 1.05 (0.30-3.66), respectively. CONCLUSION This study reveals that consumption of fish in older age reduced all-cause mortality in older people without dementia, but not in people with dementia. Fish intake should be increased in older people in general, prior to the development of dementia in the hope of preventing dementia and prolonging life

Association between fish consumption and risk of dementia: a new study from China and a systematic literature review and meta-analysis.

To assess the association of fish consumption with risk of dementia and its dose-response relationship, and investigate variations in the association among low-, middle- and high-income countries. A new community-based cross-sectional study and a systematic literature review.SettingsUrban and rural communities in China; population-based studies systematically searched from worldwide literature. Chinese adults aged ≥60 years in six provinces (n 6981) took part in a household health survey of dementia prevalence and risk factors. In addition, 33 964 participants from eleven published and eligible studies were included in the systematic review and meta-analysis. In the new study in China, 326 participants were diagnosed with dementia (4·7 %); those who consumed any amount of fish in the past two years v. those who consumed no fish had reduced risk of dementia (adjusted OR=0·73, 95 % CI 0·64, 0·99), but the dose-response relationship was not statistically significant. The meta-analysis of available data from the literature and the new study showed relative risk (RR) of dementia of 0·80 (95 % CI 0·74, 0·87) for people with fish consumption; the impact was similar among countries with different levels of income. Pooled dose-response data revealed RR (95 % CI) of 0·84 (0·72, 0·98), 0·78 (0·68, 0·90) and 0·77 (0·61, 0·98) in people with low, middle and high consumption of fish, respectively. Corresponding figures for Alzheimer's disease were 0·88 (0·74, 1·04), 0·79 (0·65, 0·96) and 0·67 (0·58, 0·78), respectively

Investigation of the Prevalence and factors Influencing Tobacco and Alcohol use among Adolescents in Nigeria: A systematic literature review

The increase in tobacco and alcohol prevalence among Nigerian teenagers necessitates the need to understand the factors influencing use. The aim of this systematic literature review was to synthesis evidence from studies on tobacco and alcohol use among Nigerian adolescents and young adults in order to determine factors influencing tobacco and alcohol use. Six databases MEDLINE, Embase, CINAHL, PsycINFO, PubMed, ScienceDirect, and Google Scholar were used to search for peer-reviewed articles reporting the prevalence and predictors of tobacco and alcohol use among adolescents/youths published between 2010 to 2022. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guided this review. From our search, twelve articles from the 6 geopolitical zones within Nigeria were included. The high prevalence of tobacco and alcohol use among Nigerian adolescents necessitates the need to understand the factors influencing use. A high prevalence rate was recorded among the male gender. Gender, age, and curiosity appear to place adolescents at extra risk for tobacco and alcohol use. Lack of parental monitoring, peer influence, low socio-economic status, low education level, stressful life events, advertisements, availability, and accessibility are factors identified to influence adolescents’ alcohol and tobacco use. Alcohol and tobacco use remains a major public health problem as it continues to contribute largely to the growing burden of diseases globally. Our review showed that adolescents’ alcohol and tobacco use behaviour is triggered by various factors on the personal, interpersonal, organisational, community, and policy levels, and these factors are understood to predict or protect against alcohol and tobacco use