Pop, heavy metal and the blues: secondary analysis of persistent organic pollutants (POP), heavy metals and depressive symptoms in the NHANES National Epidemiological Survey

Persistent environmental pollutants, including heavy metals and persistent organic pollutants (POPs), have a ubiquitous presence. Many of these pollutants affect neurobiological processes, either accidentally or by design. The aim of this study was to explore the associations between assayed measures of POPs and heavy metals and depressive symptoms. We hypothesised that higher levels of pollutants and metals would be associated with depressive symptoms.

Long-term epidemiological survey of Kudoa thyrsites (Myxozoa) in Atlantic salmon (Salmo salar L.) from commercial aquaculture farms

Kudoa thyrsites (Myxozoa) encysts within myocytes of a variety of fishes. While infected fish appear unharmed, parasite-derived enzymes degrade the flesh post-mortem. In regions of British Columbia (BC), Canada, up to 4-7% of fillets can be affected, thus having economic consequences and impacting the competitiveness of BC's farms. K. thyrsites was monitored in two farms having high (HP) or low (LP) historical infection prevalence. At each farm, 30 fish were sampled monthly for blood and muscle during the first year followed by nine samplings during year two. Prevalence and intensity were measured by PCR and histology of muscle samples. In parallel, fillet tests were used to quantify myoliquefaction. Infections were detected by PCR after 355 and 509 degree days at LP and HP farms, respectively. Prevalence reached 100% at the HP farm by 2265 degree days and declined during the second year, whereas it plateaued near 50% at the LP farm. Infection intensities decreased after 1 year at both farms. Blood was PCR-positive at both farms between 778 and 1113 degree days and again after 2000 degree days. This is the first monitoring project in a production environment and compares data between farms with different prevalence.

Studies on dietary fibre : analysis, epidemiological and physiological aspects

This thesis involves an investigation in three areas; first, a study of an enzymatic-gravimetric method for the analysis of dietary fibre; second, a survey of dietary fibre intake in an area of a developing country, and finally, some observations on the functional aspects of gel-forming dietary fibre in the rat. A simple and rapid enzymatic-gravimetric assay for both soluble and insoluble dietary fibre has been critically investigated. Reference samples were also analysed by a more comprehensive, enzymatic gas chromatographic method to allow testing of the relative accuracy of the enzymatic-gravimetric method. The enzymatic-gravimetric method was found to be highly reproducible but gave a slightly higher value for total dietary fibre than the more comprehensive method. This discrepancy is probably due to the presence of small quantities of resistant starch and protein residue which are recovered in the enzymatic-gravimetric method. In the enzymatic-gas chromatographic method, protein residue is not measured, and resistant starch is estimated, but not counted as dietary fibre. The enzymatic-gravimetric method was applied to the analysis of foods commonly consumed in the Padang region of West Sumatra in Indonesia, in order to estimate dietary fibre intake in the region. Daily intakes of usual foods were estimated by use of a 24-hour recall procedure aided by food photographs to assist in the estimation of portion size. Samples of approximately 60 of the most commonly consumed foods were collected and analysed for dietary fibre. These appear to be the first data which report values for dietary fibre in Indonesion foods and they represent a significant improvement upon the existing data on crude fibre content. Knowledge of the amounts of foods usually consumed and their dietary fibre content allowed an estimation of usual intakes of dietary fibre. Fibre intake was found to be lower than in the developing countries of Africa and was comparable to intakes measured in the U.K. This is the first study to show that in this part of South East Asia, a developing country area using polished rice as a staple food, dietary fibre intakes are as low as in Western countries. Low intakes of fibre are believed to be related to the prevalence of a range of diseases and, in this study, preliminary data on the rates of non-infective, chronic diseases were collected from the two main hospitals in West Sumatra. Chronic, non-infectious diseases such as inguinal hernia, appendicitis, haemorrhoids, diabetes mellitus, hypertension and malignant neoplasms of the rectum are relatively frequent in West Sumatra. While no firm conclusions can be drawn from these data, they do show the possibility of a relationship between low intakes of dietary fibre and the prevalence of these diseases, and suggest that further investigation is necessary. Some observations were made of the effect of gel-forming dietary fibre on stomach emptying and intestinal transit rate in the rat. Xanthan gum was added to iso-osmotic solutions to produce increased viscosity and phenol sulphonphthalein (phenol red) was used as a non-absorbable marker. Gavage feeding of solutions with a range of viscosities was used to study the effect of viscosity on the rate of stomach emptying and intestinal transit. Increased viscosity was observed to slow gastro-intestinal transit and this provides one mechanism by which dietary fibre of the gel-forming type ray improve glucose tolerance.

Using the Rose Angina Questionnaire cross-culturally : the importance of consulting lay people when translating epidemiological questionnaires

Objectives. The Rose Angina Questionnaire (RAQ) is an important measure of coronary heart disease prevalence. It has been shown to perform inconsistently across some ethnic groups in Britain. This study investigates whether the best available versions of the RAQ in Punjabi and Cantonese were linguistically equivalent to the English version.

Design. Interviews were carried out with lay people from the Pakistani, Chinese and European-origin communities in Scotland to assess the versions of the RAQ used in the Newcastle Heart Project (the best available versions). For each questionnaire item, participants were asked to elaborate on their understanding of the question and the meaning of keywords or phrases.

Results. Problems were discovered with the Punjabi and Cantonese translations of the RAQ. For example, the translation for ‘chest’ was interpreted by some Pakistani and Chinese women to mean ‘breasts’. ‘Walking uphill’ was translated in Chinese as ‘walking the hill’, without stipulation of the direction, so that some Cantonese speakers interpreted the question as pertaining to walking downhill. Many Chinese interpreted RAQ items to be referring to breathlessness rather than chest pain due to ambiguous wording.

Conclusion. Existing versions of the RAQ are unlikely to be yielding data that are cross-culturally valid or comparable. For robust health survey research in languages other than that in which the questionnaire was developed, lay assessment of questionnaires prior to and after translation is a necessity rather than a luxury.

A conduit between epidemiological research and regional health policy

OBJECTIVE: To transform data from a research setting into a format that could be used to support strategies encouraging healthy lifestyle choices and service planning within local government. METHODS: Details of the health status and lifestyle behaviours of the Geelong, Victoria, population were generated independently by the Geelong Osteoporosis Study (GOS), a prospective population-based cohort study. Recent GOS follow-up phases provided evidence about patterns of unhealthy diet, physical inactivity, smoking and harmful alcohol use. These factors are well-recognised modifiable risk factors for chronic disease; the dataset was complemented with prevalence estimates for musculoskeletal disease, obesity, diabetes, cardiovascular disease, asthma and cancer. RESULTS: Data were provided to Healthy Together Geelong in aggregate form according to age, sex and suburb. A population statistics company used the data to project health outcomes by suburb for use by local council. This data exchange served as a conduit between epidemiological research and policy development. CONCLUSION AND IMPLICATIONS: Regional policy makers were informed by local evidence, rather than national or state health survey, thereby optimising potential intervention strategies.