Background: Many western observational studies suggest moderate alcohol use is associated with better health including lower risk of cardiovascular diseases, diabetes and cognitive decline. However, the apparent benefit is susceptible to confounding by healthier attributes in moderate users. Randomized controlled trials of moderate alcohol use are infeasible. To assess the validity of these association for causal inference, I examined these associations in a setting (Southern China) with a different social patterning of alcohol use from more commonly studied western populations and using a Mendelian randomization design. Objectives: This thesis utilized two large Southern Chinese cohorts, the Guangzhou Biobank Cohort Study (GBCS) (n=30,499) and the Elderly Health Centre (EHC) Cohort (n=64,353) to examine sex-specific association of moderate alcohol use with cognitive function using observational designs. I also examined systematic differences between alcohol users and the credibility of alcohol-metabolizing genes as instruments for Mendelian randomization in GBCS. Mendelian randomization was used to examine the effect of alcohol use on cognitive function and cardiovascular risk factors and morbidity among men in GBCS. Methods: I used multivariable linear regression to examine the adjusted association of alcohol use categories (never, occasional, social weekly (EHC only), moderate, heavy and former) with cognitive function, measured by delayed 10-word recall test (phases 1-3 of GBCS), Mini-Mental State Examination (phase 3 of GBCS) and Abbreviated Mental Test (EHC), stratified by sex and age. I used multinomial logistic regression to examine the sex-specific systematic difference by alcohol category in GBCS. I used multivariable linear regression to examine the genetic association of ALDH2 with different cardiovascular risk factors and morbidities, cognitive outcomes and liver enzymes and to assess if alcohol phenotypes mediated any apparent genetic association in men. I used 2 stage least squares (2SLS) regression to examine the association of alcohol units (10g ethanol/day) with cognitive function and cardiovascular risk factors (blood pressure, lipids and fasting glucose) and morbidities (self reported cardiovascular disease and ischemic heart disease) in men in GBCS. Results: Occasional alcohol use, rather than moderate alcohol use, was consistently associated with higher cognitive function in both studies. Systematic differences among alcohol users were present. Occasional alcohol users had better health attributes while moderate users had slightly poorer attributes compared to never users. Aldehyde dehydrogenase 2 (ALDH2) was a credible instrument for Mendelian randomization. From Mendelian randomization, low to moderate alcohol use was not associated with cognitive function in men. However, it was positively associated with HDL cholesterol and diastolic blood pressure but not with fasting glucose or cardiovascular morbidity in men. Conclusions: Moderate alcohol use was not associated with cognitive function, suggesting that previous positive studies could be confounded by better health attributes in moderate users. The lack of association of alcohol use with cardiovascular morbidity despite raising HDL cholesterol is consistent with non-observational studies showing the non-causal role of HDL cholesterol in cardiovascular disease. These may suggest the apparent cardioprotection of alcohol is confounded although it remains possible that cardioprotection is population-specific via pathways other than HDL cholesterol, which require further investigations. / published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

Background: With the increasing public health concern over the alcohol related health burden and mortality globally, the World Health Organization (WHO) has listed alcohol use as the top three risk factors in Non-Communicable Disease (NCD) and the alcohol related mortality and morbidity could be avoided through early intervention and prevention. The Department of Health (DH) of Hong Kong Special Administration Region (HKSAR) has declared the alcohol epidemic was alarming with the increasing in prevalence of alcohol use and binge drinking especially among young people with the westernization of Hong Kong society. In combating local alcohol use epidemic, DH has put priority to reform health care sector system and to ensure that the local health care system is responsive to the local alcohol use problem. Brief intervention (BI) was found to be effective in dealing with at-risk alcohol use especially in primary health care settings in the various past systematic reviews. However, most reviews mainly focus on physician-led BI while the role of nurse in BI delivery in alcohol drinking had not been under great attention. The effectiveness of nurse-led BI to at-risk drinking has not been fully examined as compared with physician-led interventions in the past reviews. Evaluation of treatment components in terms of intensity, treatment components and service settings may also shed light to public health policy makers in development of local model of BI in dealing with drinking problem in the Chinese population. Objective: To investigate the effectiveness of physician-led or nurse-led BI on quantity of alcohol consumption, number of drinking days, number of binge drinking episode and health care utilization. The potentially effective treatment intensity, treatments components and setting of intervention were also investigated. Methods: All the studies published from 1990 to 2012 in MEDLINE, would be evaluated on the effectiveness of BI delivered by physicians and/or nurses to adult at-risk drinkers in primary health care settings, were searched and identified using a combination of keywords. Results: A total of 13 randomized controlled trials out of 134 articles from MEDLINE were included in this systematic review. The included studies used different outcome measurements to compare the effectiveness of BI by physicians and/or nurses in treating at-risk drinking. Similar demographics and clinical characteristics of the subjects between the intervention and control groups were reported. The studies were from 5 countries. The age range of subjects was from 14 to 75 years old. Majority of subjects drank beyond the recommended limits defined by Alcohol Abuse and Alcoholism (NIAA), United State (US). Through there were discrepancies among the results generated in the included studies on the effectiveness of physician-led and/ or nurse-led BI, the benefits of nurse-led BI in treatment of at-risk drinking cannot be dispelled and could be considered as an alternative or supplement to the physician-led BI in busy primary health care setting today. BI with at least two 5-15 minute sessions was found to be more effective than very BI with one 5-minute session only. High quality BI with all five essential treatment components (information giving, advice, goal setting, assistance and follow up) were found to be more effective than partially included treatment. BI were found effective in dealing at risk alcohol use in all General Out Patient Clinic (GOPC) while the effectiveness of BI on alcohol drinking in Special Out Patient Clinic (SOPC) needs further research to warrant the result. Conclusion: Based on this systematic review, the potential effects of nurse-led BI remain unclear in comparison with physician-led BI for at-risk drinkers. More researches on the effectiveness of BI by nurse and its cost-effectiveness as well as BI delivered by different primary health care personnel in treating at-risk alcohol drinking with long study period, especially in the Chinese population, is needed to provide further evidence on the development of local BI in local primary health care settings. / published_or_final_version / Medicine / Master / Master of Public Health

published_or_final_version / Pharmacology / Master / Master of Medical Sciences

Background The consumption of sugar-sweetened beverage (SSBs) among children and adolescents, particularly carbonated soft drinks, are always blamed to be the contributor to the epidemic of overweight and obesity. With the number of obese population increased, people become increasingly more focus on the relationship between SSB and the weight gain problems. However, because there are some characteristics of these beverages that people can get energy and happiness, so that people enjoy drinking sugar-sweetened beverage especially children who like sugar and sweet. So, people are still wondering the association between SSB and obesity. Methods A literature search was performed using Google scholar and Pubmed to locate all relevant articles in English that study the impacts of SSB on the weight gain and obesity on children and adolescent up to December 2013. Findings Eleven core references were found to study the association between SSB and the weight gain among children and adolescent including 4 randomized trial studies, 6 cross-sectional studies and 1 case-control study. Conclusions The data collected from large cross-sectional studies, especially the long-term studies shows that there is a positive association between the intake of SSB and the weight gain and obesity in children and adolescent. A case control study based on hospital shows that the children who with less soft-drink consumptions have lower prevalence of obesity and overweight. In addition, the randomized control trials indicate that the greater consumption of SSB, the easier to gain weights among children and adolescents. Although more evidence are needed, the sufficient evidence exists now are not encouraging the public to intake too many sugar-sweetened beverage as a healthy behavior. / published_or_final_version / Public Health / Master / Master of Public Health

Background Dental caries on primary and permanent teeth is a common chronic disease worldwide with negative effects on children`s quality of life, both in the present and future. Sugar intake is a risk factor for caries. However, the association between sugar-sweetened beverages (SSBs) and dental caries is unclear. Methods A systematic review of relevant literature was performed in PubMed, Cochrane Library and ScienceDirect to locate every journal article in English assessing the association between SSBs and dental caries up to May 2014. Quality assessment criteria were formed by 10 essential items in STROBE statement. Results Fourteen studies were included in the present review, of which 11 were cross-sectional studies and 3 were cohort studies. Study participants were recruited from dentistry units, schools or communities. Interview-based or self-reported questionnaires for parents or caregivers were measurement tools for exposure variables. Clinical/dental examination was used to assess the outcome variables in participating children. Decayed, missing, and filled system was used among studies to record caries status. Sources of potential bias may be measurement on exposure and outcome as well as sources and methods of participants selection. Confounding existed due to nature of observational study and possible confounders included age, gender, education and location of children as well as socioeconomic position and oral health awareness of parents. Synthesis of results suggested that there may be a positive association between SSBs and dental caries, providing evidence for policymaking and recommendations for further studies. Conclusions Sugar-sweetened beverages intake could be considered as positively associated with childhood dental caries. Prevention strategy on individual level and population level on dental caries should put more attention on SSBs. Further experimental studies or research with advanced epidemiological instruments are needed for more confident recommendations on preventive strategies. / published_or_final_version / Public Health / Master / Master of Public Health

Objective: The review aims to evaluate associations of occasional and moderate drinking with cardiovascular diseases (CVD), specifically to compare results for occasional and moderate drinking, as moderate drinking is widely investigated while occasional drinking is relatively understudied and can potentially inform whether alcohol is causally related to CVD. Methods: A systematic review was conducted by searching for observational and interventional studies from three databases (ScienceDirect, Ebscohost, and PubMed) for alcohol consumption and its association with cardiovascular health. Online internet sources were also used for more supplementary research in this literature review. Patient-oriented outcomes, primarily on heart diseases, including cardiovascular heart disease, myocardial infarction, and coronary heart disease, were extracted from all study groups. Results: Fifteen studies were included, most of which were conducted in the United States of America (9 studies). Generally, moderate alcohol consumption is associated with a reduction in CVD risks, including extensive coronary calcification, sudden cardiac death, congestive heart failure, acute coronary syndrome, ischemic heart disease. Studies also suggests that alcohol may be associated with better endothelial function and lower systolic blood pressure Current occasional alcohol use is found to be associated lower IHD mortality in men, but is not related to IHD mortality in women. Conclusion: We found consistent evidence of protective association of moderate alcohol consumption against cardio-mortality and CVD, while occasional alcohol consumption has relatively less protection against CHD deaths. Such associations were only found in studies with living controls. Only a small number of studies have studied occasional drinking, in relation to cardiovascular health. Further studies that specifically examine occasional drinking, are needed. If the biological effects of occasional drinking towards CVD are limited, then occasional drinking may indicate the magnitude of residual and unobserved confounding in the association with cardiovascular health. This will in turn inform alcohol-related policies such as alcohol duties and minimum alcohol pricing. / published_or_final_version / Public Health / Master / Master of Public Health

Chronic diseases are among the leading causes of death globally, and as much as 80% of these deaths are reported to be preventable with proper diet and lifestyle. Although extensive research has demonstrated that the increased consumption of fruits and vegetables offers protective health effects from many chronic illnesses, populations in both developed and developing nations consistently fall short of the recommended intake of 5 or more servings a day. This study investigated the effects of daily consumption of Green Smoothies for 4 consecutive weeks on blood pressure and health-related quality of life. Green Smoothies are a blended drink consisting of fruit, leafy greens and water. The study was a randomized controlled trial with a final sample of 29 volunteer participants. Data were collected at baseline and post-intervention and included anthropometric and physiologic measures, as well as a nutrition survey. The treatment group demonstrated trends toward improvements in waist circumference (p = 0.026), waist-to-hip ratio (p = 0.05), and symptoms of burden linked to diet (p = 0.04), small intestine (p = 0.04), large intestine (p = 0.05), and mineral needs (p = 0.04). Despite the lack of statistically significant reductions in blood pressure, the trend toward improvements in waist circumference and waist-to-hip ratio are considered to be useful and informative of health risk. Thus, the results of this study provide preliminary support for the consumption of Green Smoothies as a possible primary prevention effort for chronic conditions. It may also help to reduce health risks or even reverse the effects of chronic conditions.