A social ecological framework is used in this study to identify health behaviours that have the potential to affect physical activity levels in Interlake youth. Data from two cycles of the Youth Health Survey (YHS) were used to identify which demographic, individual, social and environmental factors were associated with physical activity levels of youth. Boys were found to have higher rates of physical activity than girls. As students got older their physical activity rates declined. Sex, active transportation to school, screen time, healthy eating, self perception of body image, feelings of hopelessness and feeling close to people at school were significantly associated with physcial activity levels. Important differences have been identified between the individual, social and environmental factors that can potentially affect physical activity levels of youth based on the data produced by the Interlake YHS. Individual factors have the strongest association with physical activity levels, followed by environmental factors.

Background: Ethnic and immigrant groups represent a large and growing segment of the Canadian population, however, little is known about how these groups differ in their cardiovascular risk factor profiles when compared to the White population. This thesis describes three large, population-based studies examining cardiovascular risk among people of White, South Asian, Chinese and Black ethnicity living in Ontario. It was hypothesized that ethnic groups would differ significantly in their cardiovascular risk factor profiles. Methods: The study population included 154 653 White, 3364 South Asian, 3038 Chinese, and 2742 Black subjects derived from Statistics Canada’s National Population Health Survey and Canadian Community Health Surveys. In Project 1, the age- and sex-standardized prevalence of cardiovascular risk factors, heart disease, and stroke were compared across the four ethnic groups. In Project 2, the degree to which cardiovascular risk factor profiles differed between recent immigrants and long-term residents was compared across ethnic groups. In Project 3, a subsample of the study population was used to compare the ethnic-specific incidence and age at diagnosis of diabetes. We also derived ethnically appropriate body-mass index (BMI) cutoff values for obesity for assessing diabetes risk. Results: Ethnic groups living in Ontario differ strikingly in their cardiovascular risk profiles. The Chinese group had the most favourable cardiovascular risk factor profile, with 4.3% of the population reporting ≥2 major cardiovascular risk factors (i.e., smoking, obesity, diabetes, hypertension), followed by the South Asian (7.9%), White (10.1%) and Black (11.1%) groups. For all ethnic groups, cardiovascular risk factor profiles were worse among those with longer duration of residency in Canada. Nonwhite subjects developed diabetes at a higher rate, at an earlier age, and at lower ranges of BMI than White subjects. For the equivalent incidence rate of diabetes at a BMI of 30 in White subjects, the BMI cutoff value was 24, 25, and 26 in South Asian, Chinese, and Black subjects, respectively. Interpretation: These findings highlight the need for designing ethnically tailored cardiovascular disease prevention strategies and for lowering current targets for ideal body weight for nonwhite populations.

Background: Ethnic and immigrant groups represent a large and growing segment of the Canadian population, however, little is known about how these groups differ in their cardiovascular risk factor profiles when compared to the White population. This thesis describes three large, population-based studies examining cardiovascular risk among people of White, South Asian, Chinese and Black ethnicity living in Ontario. It was hypothesized that ethnic groups would differ significantly in their cardiovascular risk factor profiles. Methods: The study population included 154 653 White, 3364 South Asian, 3038 Chinese, and 2742 Black subjects derived from Statistics Canada’s National Population Health Survey and Canadian Community Health Surveys. In Project 1, the age- and sex-standardized prevalence of cardiovascular risk factors, heart disease, and stroke were compared across the four ethnic groups. In Project 2, the degree to which cardiovascular risk factor profiles differed between recent immigrants and long-term residents was compared across ethnic groups. In Project 3, a subsample of the study population was used to compare the ethnic-specific incidence and age at diagnosis of diabetes. We also derived ethnically appropriate body-mass index (BMI) cutoff values for obesity for assessing diabetes risk. Results: Ethnic groups living in Ontario differ strikingly in their cardiovascular risk profiles. The Chinese group had the most favourable cardiovascular risk factor profile, with 4.3% of the population reporting ≥2 major cardiovascular risk factors (i.e., smoking, obesity, diabetes, hypertension), followed by the South Asian (7.9%), White (10.1%) and Black (11.1%) groups. For all ethnic groups, cardiovascular risk factor profiles were worse among those with longer duration of residency in Canada. Nonwhite subjects developed diabetes at a higher rate, at an earlier age, and at lower ranges of BMI than White subjects. For the equivalent incidence rate of diabetes at a BMI of 30 in White subjects, the BMI cutoff value was 24, 25, and 26 in South Asian, Chinese, and Black subjects, respectively. Interpretation: These findings highlight the need for designing ethnically tailored cardiovascular disease prevention strategies and for lowering current targets for ideal body weight for nonwhite populations.

Food insecurity exists when access to safe, nutritionally adequate foods is limited or uncertain, or when acquisition of these foods occurs in socially unacceptable ways (Anderson, 1990). Considerable research has focused on identifying the risk factors for and potential consequences of household food insecurity; however, few studies have investigated whether and how place of residence might influence household food insecurity. To address this gap in the literature, a mixed methods approach was used to explore the connections between risk factors, household food insecurity, and health in urban and rural settings. This dissertation comprised three studies. In the first study, secondary data were used to identify the household factors that increased the risk for household food insecurity and to examine whether place of residence moderated these relationships. Significant associations were found between household sociodemographics and household food insecurity. In addition, rural households were more likely to report household food insecurity. Although most moderation models were non-significant, a moderation effect was found for educational attainment: secondary school graduation increased the risk for household food insecurity in urban households, yet it was protective in rural households. In the second study, secondary data were used to examine the relationship between household food insecurity and poor general, physical, and mental health, and to test for a moderation effect of place of residence. In the main effects models, household food insecurity was associated with an increased likelihood of poor health on all measures. There was no evidence of urban-rural differences in these relationships. In the third study, qualitative data were used to explore household food insecurity from the perspective of urban and rural residents in Eastern Ontario. Findings revealed that urban and rural residents described similar conditions, processes, and consequences of household food insecurity; however, the unique features of the urban and rural settings influenced how people managed these experiences. In particular, certain aspects of the rural settings added to the complexity of managing household food insecurity. Overall, the results of this dissertation suggest that the urban-rural context, although important, is secondary to the primary contribution of low economic and social resources in household food insecurity.

The work described in this thesis was concerned with identifying the prevalence and risk factors associated with colonisation by the intestinal spirochaete Brachyspira pilosicoli in: humans: long term residents of Perth, Western Australia (WA) and Indonesians either living temporarily in Perth or as long term residents in urban and rural areas of Bali, Indonesia, animals: domestic animals including alpacas, birds, cattle, cats, chickens, dogs, doves, ducks, goats, horses, pigs, and sheep (housed at a wide variety of places around Perth), and a range of wild animals housed in various Zoos and wildlife centres in WA. This study shows that for humans: • Brachyspira pilosicoli was significantly more prevalent in Indonesians of all sub groups, be they temporary residents of Perth (9.4% - 216 faecal samples from 180 individuals), or long term residents of Indonesia (12.6% - 992 faecal samples from 617 individuals) compared with long term residents of Australia living mainly in Perth (0.2% of 766 sampled), even in those with gastrointestinal complaints. This suggests a relationship between a high prevalence of B. pilosicoli and living in Indonesia; • In Bali, B. pilosicoli was significantly more prevalent in the impoverished urban area of Sesetan (20.3-23.4%) where the husbandry of pigs is poor and effluent treatment is non-existent compared to four traditional farming villages (Badung, Karang Suwung, Melinggih, Payangan Desa) (3.3-22.6%). In the latter villages effluent and drainage is better and there is less likely to be contamination of drinking water • There was no significant association between the presence of B. pilosicoli and the presence of clinical symptoms including headaches, abdominal pains, diarrhoea, joint/muscular pain and constipation. • Amongst Indonesians living in Indonesia, there was no significant difference in the prevalence of B. pilosicoli between people with and without contact with animals and between farmers and other occupational groups. • Indonesians visiting Perth who were positive for B. pilosicoli originated from nine cities and five main islands in Indonesia. This suggests that B. pilosicoli is endemic throughout Indonesia. • Strain typing of isolates of B. pilosicoli showed that they were genetically heterogenous and did not show any consistent pattern with respect to geographical location, family of origin or disease status. Isolates from the same individual were sometimes unrelated, suggesting the probability of re-infection with another strain between the samplings. • Some households (~7%) had more than one member positive for B. pilosicoli. Strain analysis suggested transmission between family members, and this could be due to either faecal-oral transmission, or from a common external source, such as contaminated water. • B. pilosicoli was cultured from only 0.2% of Australians. This low prevalence may be a result of little or no exposure to B. pilosicoli due to good personal hygiene and environmental sanitation. • B. pilosicoli strain H1b and H171 that were isolated from healthy Indonesians were able to colonise mice and day-old chickens, and induced clinical signs of pasty faeces in the latter. Histological sections showed mild typhlitis and typical end-on attachment of B. pilosicoli to the caecal epithelial mucosa of the chickens. This finding suggests that the human isolates had pathogenic potential. This study showed that for animals investigated: • Intestinal spirochaetes were cultured from 46.4% (13/28) of bilbies with 14.3% (4/28) positive for B. pilosicoli. Spirochaetes were also cultured from the faeces of two Western Barred bandicoots and one (1.2%) kangaroo. • Intestinal spirochaetes were not isolated from any alpacas, cattle, goats, horses, pigs, and sheep but were detected in 40.5% of ducks, 14.3% of chickens, 14.9% of ostriches and 1.5% of cats. • Few pets that are commonly kept in households (dogs, cats and aviary birds) were colonised, suggesting that they are not an important focus of B. pilosicoli infection in Australia.

Despite the effectiveness of brief lifestyle interventions delivered in primary health care (PHC), implementation in routine practice remains suboptimal. Previous research suggests that there are many barriers to PHC clinicians addressing lifestyle risk factors, however few studies have identified the importance of various factors and how they shape practices. This thesis aimed to develop and describe a theoretical model to explain the lifestyle risk factor management practices of PHC clinicians and to identify critical leverage points for intervention. The study analysed data collected as part of a larger feasibility project of risk factor management in three community health teams in NSW, Australia, involving 48 PHC providers working outside of general practice. Grounded theory principles were used to inductively develop a model, involving three main stages of analysis: 1) an initial model was developed based on quantitative analysis of clinician survey and audit data, and qualitative analysis of a purposeful sample of participant interviews (n=18) and journal notes; 2) the model was then refined through additional qualitative analysis of participant interviews (n=30) and journal notes; and 3) the usefulness of the model was examined through a mixed methods and case study analysis. The model suggests that implementation of lifestyle risk factor management reflects clinicians??? beliefs about commitment and capacity. Commitment represents the priority placed on risk factor management and reflects beliefs about role congruence, client receptiveness and the likely impact of intervening. Capacity beliefs reflect clinician views about self efficacy, role support and the fit between risk factor management and ways of working. The model suggests that clinicians formulate different intervention expectations based on these beliefs and their philosophical views about appropriate ways to intervene. These expectations then provide a cognitive framework guiding their risk factor management practices. Finally, clinicians??? appraisal of the overall benefits and costs of addressing lifestyle issues acts to positively reinforce or to diminish their commitment to implementing these practices. The model extends previous research by outlining a process by which clinicians??? perceptions shape implementation of lifestyle risk factor management in routine practice. This provides new insights to inform the development of effective strategies to improve such practices.

Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

Thesis (M.Sc. (Clinical Tropical Medicine))--Mahidol University, 2000.