Background: Many risk factors for venous thromboembolism have been identified, but two particular exposures - the use of combined oral contraceptives and long-distance air travel - have generated considerable concern in recent years. In contrast, a possible link between venous thromboembolism and a third exposure - the use of psychotropic drugs - was first raised in the 1950s, but has received surprisingly little attention. Information about all three exposures and the risk of fatal events is limited. These risks were examined in three inter-related national population-based studies. Methods: The underlying study population included all men and women aged 15 - 59 years who died in New Zealand between 1990 and 2000, for whom the underlying cause of death was pulmonary embolism. The potential associations between fatal pulmonary embolism and the use of oral contraceptives and psychotropic drugs were explored in a general practice records-based case-control study. Non-users were the reference category for all analyses. Contraceptive supply data were used to estimate the absolute risk of death from pulmonary embolism in users of oral contraceptives. A second case-control study, in which computer-assisted telephone interviews were undertaken with the next of kin of cases who had been resident in New Zealand, and with sex and age-matched controls randomly selected from the electoral roll, investigated the possible association between long-distance air travel and fatal pulmonary embolism. Finally, the absolute risk of dying from pulmonary embolism following a long-distance flight was estimated in a descriptive study based on official migration data and deaths in recent air travellers. Results: The adjusted odds ratio for use of any oral contraceptive in the three months before the index date (the onset of the fatal episode) was 13.1 (95% CI 4.4 - 39.0). The odds ratio for formulations containing desogestrel and gestodene was about three times higher than the point estimate for levonorgestrel products; preparations containing cyproterone acetate appeared to carry the highest risk. The estimated absolute risk of fatal pulmonary embolism in current users of oral contraceptives was 10.5 (95% CI 6.2 - 16.6) per million woman-years. The adjusted odds ratio for current use of any antipsychotic was 13.3 (95% CI 2.3 - 76.3). Low-potency antipsychotics carried a 20-fold increase in risk; thioridazine was the main drug involved. Antidepressant use was also associated with a significantly increased risk (adjusted odds ratio 4.9 [95% CI 1.1 - 22.5]). Compared with non-travellers, people who had undertaken a flight of more than eight hours� duration in the preceding four weeks were eight times more likely to die from pulmonary embolism (odds ratio 7.9 [95% CI 1.1 - 55.1]). The absolute risk of fatal pulmonary embolism following air travel of more than eight hours was 1.3 (95% CI 0.4 - 3.0) per million arrivals. Conclusions: The present research was the first to have estimated the relative risks of fatal pulmonary embolism in relation to three exposures: oral contraceptive use in a population in which preparations containing desogestrel and gestodene preparations were widely used, conventional antipsychotics, and long-distance air travel. The findings were consistent with previous, and subsequent, studies of non-fatal events. Increased risks of fatal pulmonary embolism in users of antidepressants, and in people with an intellectual disability, have not been described previously and warrant further investigation. Referral and diagnostic biases are very unlikely in these studies of fatal events, and other types of bias and possible confounding are considered unlikely explanations for the findings.

Background: As a multifactorial disease glaucoma may be associated with pressure-dependent and -independent factors. Ocular hypertension (OHT) may develop into primary open angle glaucoma (POAG) for many patients. We compared groups with OHT and POAG for pressure-dependent and -independent risk factors. A high prevalence of any factor(s) could indicate a contribution to progression from OHT to POAG. Method: A sample of patients with POAG (n 438) and with OHT (n 301) were selected from those attending a tertiary referral private glaucoma practice, and data were collected regarding age and intraocular pressure at the time of diagnosis, gender, family history of glaucoma, systemic hypertension, diabetes, Raynaud's phenomenon, migraine and myopia. Results: After multivariate analysis, older age at time of diagnosis (P<0.001), myopia (odds ratio (O.R) 1.5, 95percent confidence interval (C.I)1.0-2.2; P 0.05), a family history of glaucoma (O.R 1.6, 95 percent C.I 1.1-2.3; P 0.01) and a high intraocular pressure (P 0.002) were associated with POAG. No other significant differences were found between the two groups. Conclusion: Patients who have OHT may be at higher risk of developing POAG if they also have myopia, a family history of glaucoma or are of older age.

published_or_final_version / Psychiatry / Doctoral / Doctor of Philosophy

Background: Breast cancer is the most frequent female cancer in both developed and developing world which comprising 16% of all female cancer according to WHO GLOBOCAN 2008. The statistic from Hong Kong Cancer Registry reported that breast cancer is the third commonest cause of female death in Hong Kong. Breast cancer incidence varies remarkably among developed countries. The high dietary consumption of soy isoflavones has been hypothesized to explain the lower breast cancer incidence among women in Asian countries in observational studies, but whether soy isoflavones exert estrogenic or anti-estrogenic in breast tissue remains uncertain. Objective: This systematic review was to assess the effects of isoflavone-rich soy consumption on breast cancer risk in pre- and post-menopausal women Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for conducting and reporting randomized controlled trials were followed. Data sources: A systematic review of randomized controlled trials was conducted through searching databases: MEDLINE, PubMed and Cochrane Library (2002 until March 2012). Keywords for electronic searches included: [(soy OR isoflavones) AND (breast cancer OR breast neoplasms)] limited study types to human & randomized controlled studies. Study selection: RCTs of the effects of isoflavones or supplement versus placebo or control diet among pre- and post-menopausal participants who were currently free from breast cancer. Outcome measurements: serum sex hormones and IGF profile, mammographic density and menstruation cycle length Results: 15 RCTs (1527 women) compared isoflavones with placebo or control diet for study duration ranged from 2 months to 2 years. No significant effect was found on serum sex hormones, IGF profile, mammographic density or menstrual cycle length. The effect of menstrual cycle on mammographic densities was noticed. Conclusion: The results of the systematic review did not support the hypothesis that short-term isoflavones exposure has an effect on modulating breast cancer risk. The effect of menstrual cycle on mammographic densities probably reflects the effect of hormonal changes. Null results did not necessarily contradict the inverse association between soy intake and breast cancer risk from the results of epidemiologic studies. The absence of conclusive data on the effects might be attributable to the insufficient exposure duration in the RCTs. Longer duration of soy exposure and early life exposure might be a scope for future research. / published_or_final_version / Public Health / Master / Master of Public Health

Background Radiological examination is a common diagnostic practice in modern medicine, they are not uncommonly performed during pregnancy or childhood. The potential biological effects of radiation to both the developing fetus and children are not always clear and remained controversial over many years. Physicians who care for these patients always find it difficult to evaluate the risk, and have misconceptions regarding the use of ionized radiation in pregnancy and children, which may delay the management process. Objective This study has reviewed all recent published observational studies, and analyse any possible association of prenatal or postnatal X-ray exposure from diagnostic imaging and childhood cancer risk. Methods Eligible epidemiological studies published between January 2000 and June 2013 were reviewed. These studies were found through electronic searches using Medline, PubMed, Embase, and Cochrane Database. Predetermined inclusion and exclusion criteria were applied to the identified articles Results Twenty-five articles with fourteen million participants were recruited. 17 out of 25 were case-control studies and 8 were cohort studies. All studies tried to prove an association between X-ray or CT scan exposure, and cancer of the haematopoietic system, brain and soft tissue regions. Results were summarized separately for their study methods, mode of radiation exposure and for each cancer outcome. The quality of the articles was accessed with the Newcastle-Ottawa scale. The overall OR estimate from case-control studies showed postnatal X-ray exposure positively and significantly associated with leukaemia risk (OR 1.21; 95% CI: 1.10-1.32; I2 = 3%). Cancer risk other than leukaemia are lacking in case-control studies. Recent cohort studies also showed a small but significant increase risk of leukaemia and brain tumour from childhood CT scan exposure. Conclusion This analysis had shown a small but significant increase cancer risk from X-ray or CT scans exposure in postnatal period. Varies measures should be used to minimize the radiation dose in children during radiation exposure. As long as the radiological imaging is clinically indicated and performed using appropriate scanning protocol, the benefits of radiological imaging should far outweigh the small radiation risk. / published_or_final_version / Public Health / Master / Master of Public Health

Type-2 diabetes is one of the most prevalent non-communicable diseases globally. The prevalence has increased rapidly in both developed and developing countries. Type-2 diabetes has become epidemic in China in the past three decades. With a relatively low obesity prevalence compared to western countries, such as the United States, the question has arisen as to why people in China are so susceptible to diabetes, but few studies have answered this question definitively. Asians have lower muscle mass than Caucasians which could be one possible explanation. This study aims to test the hypothesis that pubertal muscle mass acquisition, under the influence of testosterone, may be a risk factor for diabetes. This study recruited from the population-representative Chinese “Children of 1997” birth cohort with 8327 participants (88% of all infants born in April and May 1997) in Hong Kong. Participants were aged 15 years at the time of this study. The main objective was to examine the association of pubertal muscle mass with diabetes risk factors, and to examine determinants of pubertal muscle mass in this non-western setting. In June to August 2012, 502 participants from “Children of 1997” were recruited to complete a health assessment follow up at the Active Health Clinic in University of Hong Kong, including a questionnaire, blood tests and a physical examination. Multivariable linear regression was used to assess the associations of: (1) testosterone and pubertal muscle mass with diabetes risk factors, including fasting glucose, fasting insulin and homeostasis model assessment -insulin resistance (HOMA-IR), and any mediation of the association of testosterone with diabetes risk factors by pubertal muscle mass, and (2) environmental influences, including intergenerational influences, proxied by mother’s place of birth, and current life style influences (meat consumption and physical activity), with pubertal muscle mass. Higher pubertal testosterone was associated with lower fasting glucose (-0.008, 95% confidence interval (CI) -0.015 to -0.002), fasting insulin (-0.44, 95% CI -0.57 to -0.31) and HOMA-IR (-0.090, 95% CI -0.12 to -0.063) after adjusting for potential confounders, i.e, sex, birth weight, highest parental education, mother’s place of birth and physical activity. The association was partially mediated by skeletal muscle mass and body fat percentage. Skeletal muscle mass was negatively associated with fasting glucose (-0.017, 95% CI -0.025 to -0.009), insulin (-0.876, 95% CI -1.033 to -0.719), and HOMA-IR (-0.180, 95% CI -0.214 to -0.147) after adjusted for potential confounders. High meat consumption (0.176, 95% CI 0.000 to 0.351) and physical activity (0.157, 95% CI 0.059 to 0.254) were both associated with higher skeletal muscle mass in adolescents; however birth weight and mother’s place of birth had no influence on pubertal skeletal muscle composition. Higher pubertal muscle mass and testosterone are association with better glucose metabolism in adolescence. Food intake and physical activity may also influence the development of skeletal muscle, thus adolescence may be a sensitive period for the development of diabetes where interventions to increase muscle mass could have long-term protective effects. / published_or_final_version / Public Health / Master / Master of Philosophy

published_or_final_version / abstract / toc / Psychiatry / Master / Master of Philosophy

No description available.

No description available.

Bakgrund: Fibromyalgi är ett syndrom som kännetecknas av utbredd smärta, överkänslighet vid beröring men även att övriga delar av kroppen påverkas. Metod: En litteraturstudie har genomförts där 10 stycken vetenskapliga artiklar har analyserats och utgjort resultatet. Syfte: Huvudsyftet är att undersöka möjliga riskfaktorer som kan påverka utvecklandet av fibromyalgi. Resultat: Studiens resultat har tagit upp fyra teman med tänkabara riskfaktorer. Traumatiska barndomshändelser, där både fysisk och verbal misshandel och sexuellt utnyttjande var riskfaktorer. Att bli utsatt för trauma som vuxen, där fysisk misshandel, operation och arbetsrelaterad skada ingick, var också en riskfaktor. Stress och ett högt BMI-värde var också riskfaktorer relaterade till utvecklandet av fibromyalgi. Diskussion: Studiens resultat visade på att det är flera riskfaktorer som påverkar utvecklandet av detta syndrom. Alla som utsätts för en av dessa riskfaktorer utvecklar dock inte fibromyalgi, utan med största sannolikhet så är det en kombination av flera riskfaktorer som gör att man utvecklar fibromyalgi. Slutsats: Det behövs mer forskning för att studera sambandet mellan fysiska, psykiska och sociala riskfaktorer. / Background: Fibromyalgia is a syndrome characterized by widespread pain, hypersensitivity to the touch but other body areas are also affected. Method: A literature study was conducted in which 10 scientific articles were analyzed and discussed. Purpose: The main purpose was to investigate possible risk factors that may affect the development of fibromyalgia. Results: The results of this study raised four themes describing risk factors. Traumatic childhood events, including both physical and verbal abuse and sexual abuse, were risk factors. Becoming a victim of trauma as an adult, where physical abuse, operation and work related injuries were included, was a risk factor as was stress and a high BMI. Discussion: Study results showed that there are many risk factors that affect the development if this syndrome. All persons exposed to one of these risk factors however does not develop fibromyalgia, so most likely it is a combination of several risk factors that makes the development of fibromyalgia possible. Conclusion: More research is needed to study the connection between physical, psychological and social risk factors.