This work stems from an increased effort to improve cancer survival rates through earlier diagnosis, which itself may be achieved through prompt medical help-seeking for symptoms. This thesis focuses on responses to symptoms potentially indicative of a gynaecological cancer; a group of cancers that pose a significant threat to women, and yet are under-represented in the literature. Four studies were conducted. Studies One and Two (n=1392 and n=1000, respectively) were population-based surveys of women, measuring awareness of cervical and ovarian cancer risk factors and symptoms, respectively. Study two also measured hypothetical help-seeking. Study three was a survey of a nationally-representative sample of women (n=911), which explored responses to real symptoms that were potentially indicative of a gynaecological cancer. Building on study three, study four explored responses to symptoms at a deeper level, through in-depth, one-to-one interviews with women who had recently, or were currently, experiencing a symptom potentially indicative of a gynaecological cancer. Awareness of symptom and risk factors for cervical and ovarian cancer was low overall. Women anticipated seeking help promptly for symptoms of ovarian cancer, however, when faced with real symptoms, outside of the context of cancer, help might not be sought as promptly. I found that women with symptoms respond in many different ways. Mapping my findings onto the Model of Pathways to Treatment, I identified a number of different influences which may be more important at the appraisal stage, including what can be expected as part of being a woman and those which may be more important at the help-seeking stage, such as feeling justified in seeking help. More education is needed about the symptoms and risk factors for gynaecological cancers. Further, campaigns encouraging women to seek help for symptoms should include messages which target those variables that may lead women to wait longer before seeking help, such as misattribution of symptoms.

Background: The impact of neighbourhood physical environments on physical activity and health is widely acknowledged, with much research conducted to identify key factors. Results have been mixed, partly due to inconsistencies in how neighbourhoods are defined. This thesis examines relationships of physical environments with physical activity, and with depression, exploring influence of neighbourhood operationalisation. Method: Physical activity and depression outcomes were derived from a sample drawn from the seventh wave of the Whitehall II study conducted in 2004/5, and depression outcomes were also taken from the 2008 Health Survey for England. Neighbourhoods were operationalised at three levels of administrative geography and as residential postcode-centred GIS software-computed zones. Four main exposure variables were specified: a greenspace measure was constructed from the Generalised Land Use Database; an objective measure of environmental quality was derived from metadata of the Multiple Environmental Deprivation Index, and a subjective one from the 2008 Place Survey; and a walkability measure was constructed using GIS, drawing on several geographical databases. Multivariate logistic regression was used to measure statistical associations between exposures and outcomes, with adjustment for individual-level sociodemographic factors and area-level deprivation, and multilevel modelling was performed to estimate the contribution of neighbourhood characteristics relative to those of individuals to variation in outcomes. Results: Neighbourhood physical environments accounted for a small proportion of variation in all outcomes. Nevertheless, significant associations were found between all exposure variables and physical activity, independently of individual-level sociodemographic factors and area-level deprivation, the direction dependent on outcome specification. Only objectively measured environmental quality was significantly and independently with depression, with lower quality giving higher odds of this outcome. Strengths of associations were not substantively affected by neighbourhood operationalisation. Conclusion: This thesis increases understanding of physical environment attributes relevant to physical activity and depression in a European context and how neighbourhoods in which they are measured may best be defined.

The existence of the illicit tobacco trade has serious implications for tobacco control efforts as it encourages smoking by providing tobacco products at a cheaper price. Although this illicit trade has serious ramifications for public health in England, there is very limited data on its nature, the extent of its use and smokers’ views on illicit tobacco. This thesis aimed to address this by utilising a mixed methodology approach which consisted of population based surveys of English smokers and in-depth face-to-face interviews with smokers. Prevalence of illicit tobacco use appeared to decrease between 2007-8 and 2012, but there was an increase from 2010-11 to 2012. ‘Under the counter’ tobacco purchases in retail shops emerged as a prominent source of illicit tobacco, although smokers were able to access a number of illicit sources. Smokers who exclusively purchased illicit tobacco paid much less for their tobacco products compared with those who reported exclusive duty-paid tobacco purchases. Report of illicit tobacco use was more likely in younger smokers, males, smokers in low socio-economic groups, smokers of ‘roll your own’ tobacco and those with high tobacco dependence in 2012. However, this changed with each survey, as illicit tobacco use appeared to become more widespread across socio-demographic sub-groups. Illicit tobacco users reported lower levels of motivated to quit smoking. However, smokers in the interview study reported that loss of access to illicit tobacco would drive them to think about quitting or cutting down on their smoking. The interview study revealed that smokers were able to easily access illicit tobacco in their communities and social circles. In addition, smokers viewed the illicit tobacco market and illicit traders approvingly as providing a means of accessing affordable tobacco products. Furthermore, they were unperturbed by the illegality and associated criminality of illicit tobacco trade. Due to the nature of this illegal activity, further research should investigate how the illicit tobacco market evolves in response to policy efforts.

Colorectal cancer (CRC) is an important source of disease burden in the United Kingdom and developed world. It is often preventable through certain forms of screening of asymptomatic individuals, allowing for the timely detection and removal of pre-cancerous polyps (adenomas). It can also reduce mortality (in individuals who already have CRC) by detecting it at an earlier, more treatable stage. Computed Tomographic colonography (CTC) is a comparatively new test that is capable of detecting adenomas before they transition into cancer, meaning that it can identify people for whom polypectomy is warranted. Like the “gold standard” test of colonoscopy, it can detect most adenomas. It may also be perceived more positively than colonoscopy by screening invitees because the exam is less invasive, potentially increasing uptake and improving population health outcomes. Another possible advantage of CTC over colonoscopy is that it is possible to replace the burdensome full-laxative bowel preparation with reduced- or even non-laxative alternatives. However, these are likely to be associated with a reduction in sensitivity and specificity, resulting in more false negatives and false positives, and this may detract from its overall public acceptability. The main aims of this PhD were to investigate the public’s views about the optimum method of carrying out CTC, taking into account the trade-offs involved in bowel preparation options, and test whether a particular form of CTC had the potential to increase screening uptake compared with other preventative CRC screening tests (colonoscopy and flexible sigmoidoscopy). Chapter 1 consists of the background to CRC, screening, and the relevant tests. Chapter 2 introduces the issues of screening test preferences and uptake. Chapter 3 (Study 1) reports on a qualitative discussion group study that served as an initial exploration of public perceptions, values and preferences regarding CTC and colonoscopy. Chapter 4 (Study 2) reports on a qualitative interview study that compared patients’ experiences with CTC following non- or full-laxative preparation in order to inform a further qualitative study in Chapter 5 (Study 3), which explored public perceptions and preferences for different bowel preparations for CTC, specifically taking into account the trade-offs. A more systematic assessment was planned to quantify the extent to which preparation tolerability, sensitivity and specificity were valued and Chapter 6 (Study 4) consisted of a review of previous studies that used the selected approach (conjoint analysis) with the aim of identifying strengths and weaknesses in the existing literature. These findings were drawn on when designing Study 5 in Chapter 7, which consists of a particular form of conjoint analysis (a discrete choice experiment) to quantify public values of the main attributes of interest for CTC. The final study in Chapter 8 (Study 6) randomised participants to receive a hypothetical screening invitation for one of several preventative tests in order to measure how uptake of different forms of CTC might compare with colonoscopy and flexible sigmoidoscopy. Chapter 9 refers to findings from psychology that aims to broaden the perspective of how studies assess and interpret stated preferences for and perceptions regarding screening tests. Findings are then synthesised in Chapter 10, taking into account this broader literature. Participants consistently discriminated between CTC and colonoscopy across studies and appraised the former less negatively in terms of experiential characteristics. Participants were also consistent in anticipating the experience of non- and reduced-laxative preparation less negatively than full-laxative preparation. Results were more mixed in terms of appraisals of sensitivity and specificity in the context of CTC bowel preparation. The qualified interpretation presented here is that sensitivity is an influential attribute but specificity is not, when both are defined within a range of values considered plausible. Hence, although sensitivity and the anticipated experience of preparation were both important attributes, perceived gains arising from reducing preparation burden were offset by perceived costs from the corresponding reduction in diagnostic performance of CTC, leading to no clear overall preference for a particular preparation method. Furthermore, there was no evidence that screening uptake would be higher for different forms of CTC, or other preventive screening tests. The most robust method of confirming these findings would be direct comparisons of the tests in trials assessing actual screening behaviour.

Background: In England, 70% of young people consume soft drinks on a regular basis which increases the likelihood of obesity and dental caries. Many young people often visit the dentist; however primary dental care has been an underutilised research setting for delivering and evaluating dietary interventions. Motivational Interviewing (MI) has been shown to be effective in behaviour change. Therefore, this study provides an opportunity to assess an obesity intervention to reduce soft drinks consumption among young people attending NHS dental practices. Aims: To conduct a feasibility trial of an MI intervention to reduce soft drinks consumption among young people attending primary dental care practices in North Central London (Camden, Islington, and Haringey). Methods: The initial developmental phase explored dental teams’ attitudes, behaviours and perceived barriers in delivering prevention, using a mixed methods approach (focus groups followed by a questionnaire survey). A purposive sample of 11 out of 22 dental practices was selected from the study area for the four focus groups (two with dentists and two with dental care professionals). A cross-sectional survey of all NHS dentists was also conducted using a self-complete questionnaire. Descriptive analysis of the questionnaire data was undertaken and differences by the age and sex of the sample were assessed. A cluster feasibility trial with embedded process evaluation was then undertaken in the second phase of the study. Participants: Ten randomly allocated NHS dental practices recruited 39 overweight or obese young people (11-16 years). Intervention: 3-4 MI sessions. The three main outcomes were: mean daily consumption of sugary soft drinks using a 24 hour dietary recall, body mass index (BMI) and waist circumference. Outcomes were measured at baseline and at 6 month follow-up. Process evaluation outcomes: Recruitment, retention, fidelity and acceptability of the intervention were assessed using mixed methods. MI Fidelity was assessed using the Motivational Interviewing Treatment Integrity Code (MITI). Thematic analysis was used to analyse the qualitative data and descriptive analysis for the quantitative data. The study was approved by the local Ethics Committee (10/H0722/2). Results: Of the 300 eligible respondents, 164 questionnaires were returned (response rate: 54.7%). In Phase I, there were broad similarities in the themes that emerged from the four focus groups and the questionnaire survey. The majority of respondents strongly agreed that NHS dentists had a role to play in smoking cessation counselling, diet and alcohol advice. For dentists, prevention was viewed to be part of their ethical obligation. A high proportion of respondents 95.7% delivered oral hygiene advice, 85.4% provided diet advice, and 76.7% offered smoking cessation advice always or frequently. Barriers to delivering prevention included organisational factors (lack of adequate remuneration, bureaucracy), patient-related factors (motivation and compliance), and clinician-related factors (lack of training and resources). There was significant variation in providing prevention by the age and sex of dentists with female and younger dentists more likely to provide certain aspects of preventive care. Phase II- 10 dental practices were recruited (5 control and 5 intervention). Out of 149 potential participants, 39 (26.2%) conformed to the eligibility criteria, 5 (12.8%) withdrew from the study, and 3 (7.6%) were lost to follow-up, resulting in a retention rate of 79.5%. Facilitators of study implementation included the use of a screening questionnaire, support from the research team and incentives for young people and dental teams. In terms of acceptability, participants reported that the study had a positive impact on their knowledge or behaviours. At follow-up, soft drinks consumption decreased. Dental teams valued being involved in research. They recognised the challenges in recruiting young people and employed varying mechanisms to overcome them. Intervention fidelity revealed the MI practitioners to be proficient in MI and there was little variation in proficiency among the practitioners. Conclusions: Dentists in the study area were actively involved and had a generally positive attitude towards delivering prevention in primary dental care. The intervention was acceptable and feasible among dental teams and young people. MI is a feasible tool for reducing sugary soft drinks consumption among overweight young people attending dental practices. Further research is required to assess its effectiveness in primary dental care.

The overall aim of this research study was to assess whether there are socioeconomic gradients in various oral health outcomes (caries experience, decayed teeth, traumatic dental injuries and self-rated oral health) of adolescents, 12-15 years of age living in the city of New Delhi, India and to assess the various material, psychosocial and behavioural factors influencing this gradient. Various studies conducted across the world have reported that children and adolescents belonging to lower socioeconomic groups compared to higher socioeconomic groups have poorer oral health status. This relationship is present in a stepwise manner across the entire spectrum of socioeconomic hierarchy commonly known as social gradient. Studies conducted in India conversely are inconclusive and provide conflicting evidence. No attempt has been made in assessing the role of psychosocial (social capital and social support), behavioural and material (standard of living) factors in affecting the socioeconomic gradients in oral health in India especially considering adolescents living in deprived neighbourhoods. The proposed study is an attempt to address this gap in the scientific literature. A cross sectional survey was conducted with a sample of 1386 adolescents living in 3 diverse residential areas of New Delhi (urban slums, resettlement colonies and middle/ upper middle class homes). A clinical examination was undertaken to assess the oral health status of the sample and an interviewer administered questionnaire was used to gather relevant behavioural and social data. Disparities in various oral health outcomes was found between adolescents from different residential areas living in New Delhi. Clear monotonic socioeconomic gradients were observed in caries experience and number of decayed teeth while a threshold effect was observed in dental trauma with adolscents from urban slums and resettlement colonies showing significantly higher levels of dental trauma in comparison to their middle class counterparts. No significant gradient was observed in poor self-rated oral health. Different material, psychosocial and behavioural factors had no significant impact on the observed gradients in various oral health outcomes showing that area of residence is a very strong predictor of oral health and there is a need to design policies which aims at improving health by taking action on the broader structural determinants of health.

Background: Traumatic dental injuries (TDIs) are one of the most common body injuries and constitute an important public health problem. These injuries are considerably more common among adolescents, and can lead to pain, physical impairment, emotional distress and negative impact on the quality of life. Theories link most types of injuries to individual behaviours within a complex matrix involving both the physical and social environments. However, most of the aetiological studies on TDIs focus on proximal risk factors and overlook the underlying more distal determinants. This PhD thesis aimed to assess whether certain behavioural and psychosocial determinants were associated with the prevalence of TDIs among adolescents in Riyadh, Saudi Arabia, with a particular focus on the role of their risk-taking behaviours and peer influence. Methods: A stratified two-stage cluster sample of 902 students (461 boys and 441 girls) was randomly selected from adolescents attending 1st and 2nd years of public and private secondary schools in Riyadh, using a self-weighting design for both sexes and school types. Data were collected through clinical examination and questionnaire. TDIs were clinically diagnosed using a modified version of the WHO classification for epidemiological studies. The clinical examination also included assessment of overjet and lip coverage. The questionnaire was based on the WHO Health Behaviour in School-Aged Children questionnaire and the CDC Youth Risk Behaviour Surveillance System, assessing exposures risk-taking behaviours and peer influence, as well as demographics, socio-economic status and physical activity. The differences in prevalence of TDIs between the different groups of the covariates and exposures were calculated. Then, Poisson regressions with a robust error variance were used to estimate adjusted prevalence ratios (relative risks) of TDIs between the different exposures to provide sequential adjustment for confounding factors. The models were further checked for interactions between the main exposure and the peer influence variables. Results: Overall, 42.6% of adolescents had TDIs to their anterior teeth (Boys: 59.4%; Girls: 24.9%). After adjusting for age, sex, father’s education, nationality, physical activity and overjet >3mm, smoking was significantly associated with TDIs among girls (RR 2.50; 95% CI 1.42–4.41), and the same was the case among boys for fights (RR 1.46; 95% CI 1.19–1.79), for spending time with friends after school on more than three days a week (RR 1.25; 95% CI 1.07–1.46) and for having peers who carried weapons (RR 1.19; 95% CI 1.01–1.40), compared to their counterparts. TDIs were also significantly associated with both boys and girls who carried weapons (RR 1.36; 95% CI 1.12–1.66), had multiple risk-taking behaviours (RR 1.44; 95% CI 1.20–1.72) and had less than three close friends (RR 1.19; 95% CI 1.00–1.42) compared to their counterparts. The risk of TDIs was intensified among adolescents who carried weapons and had multiple risk-taking behaviours when they lacked peer support (RR 2.18; 95% CI 1.05–4.57 and RR 2.18; 95% CI 1.05–4.57, respectively) compared to their counterparts who had supportive peers (RR 1.28; 95% CI 1.01–1.62 and RR 1.36; 95% CI 1.11–1.68, respectively). Conclusions: Adolescents in Riyadh, particularly boys, had a very high prevalence of TDIs. Risk-taking behaviours (smoking, fights and carrying weapons) and negative peer influence (having peers who carried weapons) indicated an increased risk of TDIs among those adolescents independent of their age, socioeconomic status, physical activity and incisor overjet level. Negative peer influence (lack of peer support) intensified the association between risk-taking behaviours and TDIs.

We use mathematical models to explore the evolutionary implications of health interventions affecting age-dependent mortality schedules in two contexts, antihelminthics targeting parasitic nematodes, and programs directed against malaria vectors. We show that interventions targeting parasitic nematodes can exert selection pressure to either shorten.or extend the time to maturity, depending on the details of worm mortality functions with and without the intervention. Interventions may therefore generate selection favouring later-maturing, larger and more fecund worms, rather than inevitably favouring the evolution of smaller, less fecund and hence potentially clinically less damaging worms as previously assumed. The evolution of insecticide-resistant mosquitoes threatens conventional public health programs targeting malaria vectors. By exploiting the high mortality rates of wild mosquitoes and the delay between malaria infection and infectiousness in mosquito hosts, late-life-acting (LLA) insecticides which kill only older mosquitoes can in principle provide effective transmission control in combination with very low selection for resistance. We develop a novel mathematical model to evaluate the potential of such pesticides and find that theoretical LLAs which affect only mosquitoes above a specific age can offer transmission control comparable with conventional insecticides, combined with very low selection for resistance. Benefits are maximised by generating lower mortality in mosquitoes not infected with malaria, and contacting and killing mosquitoes prior to biting.

Background & objectives: There is an extensive body of literature suggesting that social relationships are beneficial for health. The present study explores this association by testing two hypotheses. The first hypothesis is that people who are more socially orientated have better health than those who are less socially orientated. The second hypothesis has two parts the first part is that people who have strong altruistic and collectivistic orientations have better health than those with less strong altruistic and collectivistic orientations the second part is that altruistic and collectivistic orientations relate directly to health over and above the potentially mediating effect of social relationships on them. The main idea of the study is to introduce an integrated epidemiological model of the association between sociability and health which will include not only social relationships but also their determinants such as collectivism and altruism.;Methods: The study instrument measures health, social relationships, individualism, collectivism and altruism and was addressed to a sample of 926 people above 40 years old of both sexes in Greece. The main health outcomes of the study are self-reported mental and general health. The statistical analysis encompasses descriptive statistics, bivariate analysis, factor analysis, multivariate linear regression modeling and structural equation modeling.;Results: Through factor analysis three individualism-related, three collectivism-related and four altruism-related factors emerged. The multivariate analysis shows that most of the collectivism- and altruism-related factors associate with social relationships and two of them (Volunteering and Horizontal Collectivism) with both health outcomes. Also it suggests that friendships associate with general health and family relationships with mental health and that the associations of Horizontal Collectivism with general health and Volunteering with mental health are over and above social relationships. The structural equation models show that the proposed conceptual model is valid.;Discussion: Both hypotheses should partially be accepted there is indication that people who are more socially orientated have better health some of the determinants of social relationships associate significantly with health and in some cases these associations hold even over and above social relationships.

Background: Coronary mortality rates amongst South Asian populations are higher than in White populations in the UK. The contribution of incidence and prognosis of coronary disease to the higher coronary mortality rates amongst South Asian populations is unknown. Incident coronary disease commonly presents as angina and non-fatal myocardial infarction rather than as fatal events. Aim: This thesis sought to investigate the incidence and prognosis of differing clinical presentations of coronary disease such as angina and myocardial infarction in South Asian compared to White populations in the UK. Methods: Four new prospective studies, one aetiologic (South Asian N=580 initially healthy) and three prognostic (N=2189 with suspected new-onset stable angina, N=502 undergoing coronary angiography and N=3037 with acute coronary syndromes) were examined, using multi-variate regression analyses. A systematic review and meta-analysis of these and previously published studies was performed. Results: • Incidence of angina was higher in South Asian than in White people in a healthy population, and angina was similarly valid in predicting a poor prognosis in both ethnic groups compared to those with no chest pain. • In those with chronic angina, South Asian patients did not have a higher future risk of myocardial infarction and death than White patients, but had a worse symptomatic prognosis following coronary revascularisation when compared to White patients. • South Asian patients had no worse a prognosis for mortality than White patients after myocardial infarction • On meta-analysis, incidence of fatal and non-fatal coronary disease was higher in South Asian populations compared to White populations whilst prognosis of coronary disease in South Asian populations was not worse than in White populations. Conclusions: Increased coronary mortality rates in South Asian populations compared to the White populations are due to the higher incidence of fatal and non-fatal coronary disease in South Asian people, as the prognosis of manifest coronary disease in South Asian people is not worse than in White people.