Risk factors and health effects of overweight and obesity in older adults

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Introduction: The older adult population is rapidly increasing, and overweight and obesity prevalence is fast rising in older people globally. It is unclear whether excess body weight in older age reduces or increases the risk of incident dementia and whether it prolongs survival. Evidence of the risk factors for overweight and obesity in older age is scarce. This thesis investigated the risk factors and health effects of overweight and obesity in older age, with a focus on their impacts on incident dementia and all-cause mortality. Methodology: This study employed a mixed method of quantitative and qualitative approaches that are based on a large cohort study dataset from China and two focus group discussions from the United Kingdom. The cohort consisted of 3,336 participants in total: 1,736 aged >= 65 years recruited from urban areas in 2001 and 1,600 aged>=60 years from rural areas in 2003 in Anhui province, China. In the standard methods of interview, they were documented for sociodemographic, lifestyle, social network, disease, and other risk factors at the baseline survey. Body Mass Index (BMI) and waist circumference (WC) were measured, and dementia was diagnosed by the GMS-AGECAT for each of the participants. The cohort members were followed up for 10 years to monitor mortality and examine the cause of death. There were three waves of interview for surviving cohort members during the follow up to document incident dementia apart from the causes of mortality. The data of the Anhui cohort study were analysed in multivariate Logistic and Cox regression models. Two focus groups research were conducted in Wolverhampton UK. It included 12 twelve older adults who were recruited from the community through their place of worship. The focus group data were collected in a digital audiotape. They were transcribed verbatim and analysed thematically. Findings: The data from the cohort wave three surveys showed that the risk factors for overweight and obesity in older people included female gender, low education, low income, residing in urban areas, being married, watching TV/reading newspapers, and hypertension at baseline. Over the 10-year follow-up, 271 participants were diagnosed as having incident dementia. The continuous BMI at baseline increased the risk of incident dementia (multivariate-adjusted odds ratio (OR) 1.06, 95%CI 1.00-1.11). There was no significant increase in OR in participants who were overweight (1.34, 0.91-1.98) and obese (1.52, 0.86-2.70) when compared to normal weight, but separate data by gender showed that dementia risk was significantly increased in men with overweight (3.09, 1.65-5.77) and obesity (4.19, 1.75-10.03) and not in women (0.74, 0.43-1.27; 0.72, 0.32-1.64). The prediction was similar regardless of different adiposity measures used; the risk of dementia was elevated in non-smokers with obesity measured by BMI (4.28, 1.46-12.53) and in non-smokers with waist circumference classed as action level two (3.19, 1.04-9.77). The Anhui cohort data did not show significantly reduced mortality in older people with overweight (HR 0.78, 95%CI 0.56-1.08) and obese BMI (0.79, 0.47-1.33) when compared to normal BMI. There were no gender differences. But the risk of all-cause mortality was significantly increased in older people with underweight (2.04, 1.25-3.33), and the sex-stratified data analysis showed a stronger effect in men (2.31, 1.21-4.42) and not in women (1.59, 0.73-3.44). The focus group data also supported such findings of deleterious effects of overweight and obesity by major themes including theme-harm, impairment, and mortality. Conclusions: Overweight and obesity in older age increased the risk of incident dementia. They were not significantly associated with reduced risk of mortality although underweight increased the risk. Curtailing overweight and obesity and maintaining normal weight in older age could help reduce the risk of developing dementia and extend survival

Prevalence and determinants of undetected dementia in the community: a systematic literature review and a meta-analysis

Objectives Detection of dementia is essential for improving the lives of patients but the extent of underdetection worldwide and its causes are not known. This study aimed to quantify the prevalence of undetected dementia and to examine its correlates. Methods/setting/participants A systematic search was conducted until October 2016 for studies reporting the proportion of undetected dementia and/or its determinants in either the community or in residential care settings worldwide. Random-effects models calculated the pooled rate of undetected dementia and subgroup analyses were conducted to identify determinants of the variation. Primary and secondary outcome measures The outcome measures of interest were the prevalence and determinants of undetected dementia. Results 23 studies were eligible for inclusion in this review. The pooled rate of undetected dementia was 61.7% (95% CI 55.0% to 68.0%). The rate of underdetection was higher in China and India (vs Europe and North America), in the community setting (vs residential/nursing care), age of <70 years, male gender and diagnosis by general practitioner. However, it was lower in the studies using Mini-Mental State Examination (MMSE) diagnosis criteria. Conclusions The prevalence of undetected dementia is high globally. Wide variations in detecting dementia need to be urgently examined, particularly in populations with low socioeconomic status. Efforts are required to reduce diagnostic inequality and to improve early diagnosis in the community

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

Determinants of fish consumption in older people: a community-based cohort study

Objectives: Habitual fish consumption and its determinants in older people have not been well investigated. We addressed these issues through a population-based cohort study. Methods: In 2001-2003 we interviewed a random sample of 3336 residents aged ≥60 years in China, documenting socioeconomic status (SES) and disease risk factors. In 2007-2009 we re-interviewed 1757 survivors, additionally surveying average self-reported intake of fish over the past two years. Results: Of 1757 participants, 1697 responded to the fish consumption questionnaire; 23.0% of whom had “never eat” fish, 43.4% “once a week”, 26.9% “more than twice a week”, and 6.7% “≥once a day”. There was an inverse association of fish consumption with older age (multivariate adjusted odds ratio 0.64 [95% CI 0.45-0.92] and 0.35 [0.24-0.52] at ages of 75-79, and ≥80 years), female gender (0.63, 0.47-0.84), smoking (0.65, 0.48-0.88), living in a rural area (0.10, 0.07-0.15), having educational level of ≤primary school (0.10, 0.05-0.19), occupation of peasant (0.08, 0.05-0.14), low income (0.11, 0.07-0.18), financial difficulties (0.25, 0.18-0.34), being never married/divorced (0.48, 0.28-0.81), having undetected hypertension (0.71, 0.55-0.91), depression (0.50, 0.29-0.84) and dementia (0.64, 0.41-0.98). However, participants with central obesity and heart disease at baseline had increased odds of fish consumption. Separate data analysis for different levels of fish consumption showed a dose-response trend for these associations. Conclusion: In older Chinese, there are large socioeconomic inequalities, and certain lifestyle, psychosocial factors and health-related conditions are strong determinants of fish consumption. Such information is important for future development or refinement of effective dietary interventions targeting older adults

The influence of granulating solvents on drug release from tablets containing grewia gum

The influence of granulating solvents on release of indomethacin from tablets containing grewia gum was evaluated. The tablets were prepared by either wet granulation or direct compression. The experimental design was based on a 3x5 factorial design. The drug/gum ratio was varied at three levels, 2:1, 1:1 and 1:2. At each of these levels, the solvent effects were examined at five levels namely, 100% water, 75% water and 25% ethanol, 50% each of water and ethanol, 25% water and 75%. These were compared with a fifth level which is a matrix tablet prepared by direct compression without any solvent. The dissolution rates of the tablets were determined using a rotating paddle dissolution apparatus. The cumulative percent of drug dissolved from the three matrix tablets are not significantly different (p>0.05). Although no rank correlation was observed among the tablets prepared with 100%, 75% and 50% water, drug release from the tablets prepared with 25% water are significantly lower than the other wet granulated tablets, but higher than the matrix tablets. The granulating solvent influenced the release of drug which increased with increase in the water content. Key Words: Grewia gum: Granulating solvents; Release mechanisms. Journal of Pharmacy and Bioresources Vol.1(1) 2004: 76-8