The effects of ambient temperature and heatwaves on daily Campylobacter cases in Adelaide, Australia, 1990-2012.

Campylobacter spp. is a commonly reported food-borne disease with major consequences for morbidity. In conjunction with predicted increases in temperature, proliferation in the survival of microorganisms in hotter environments is expected. This is likely to lead, in turn, to an increase in contamination of food and water and a rise in numbers of cases of infectious gastroenteritis. This study assessed the relationship of Campylobacter spp. with temperature and heatwaves, in Adelaide, South Australia. We estimated the effect of (i) maximum temperature and (ii) heatwaves on daily Campylobacter cases during the warm seasons (1 October to 31 March) from 1990 to 2012 using Poisson regression models. There was no evidence of a substantive effect of maximum temperature per 1 °C rise (incidence rate ratio (IRR) 0·995, 95% confidence interval (95% CI) 0·993-0·997) nor heatwaves (IRR 0·906, 95% CI 0·800-1·026) on Campylobacter cases. In relation to heatwave intensity, which is the daily maximum temperature during a heatwave, notifications decreased by 19% within a temperature range of 39-40·9 °C (IRR 0·811, 95% CI 0·692-0·952). We found little evidence of an increase in risk and lack of association between Campylobacter cases and temperature or heatwaves in the warm seasons. Heatwave intensity may play a role in that notifications decreased with higher temperatures. Further examination of the role of behavioural and environmental factors in an effort to reduce the risk of increased Campylobacter cases is warranted.

The influence of motor function on processing speed in preterm and term-born children.

This study investigates the relationship between motor function and processing speed in preterm children. Processing speed was compared in 145 adolescents, born 25-41 weeks gestational age, utilizing tasks including differing motor demands. The influence of motor cortex excitability and functional motor skills on task performance was assessed. For tasks with motoric demands, differences in performance between preterm and term-born children were mediated by the relationship between gestational age, corticomotor excitability, and motor function. There were no differences in non-motor processing speed task performance between preterm and term-born children. Measures of processing speed may be confounded by a timed motor component.

Maternal factors and the risk of birth defects after IVF and ICSI: a whole of population cohort study.

OBJECTIVE: To assess the contribution of maternal factors to major birth defects after in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and natural conception. DESIGN: Retrospective cohort study in South Australia for the period January 1986 to December 2002. SETTING: A whole of population study. POPULATION: A census of all IVF and ICSI linked to registries for births, pregnancy terminations, and birth defects (diagnosed before a child's fifth birthday). METHODS: Odds ratios (ORs) for birth defects were calculated among IVF, ICSI, and natural conceptions for maternal age, parity, pre-pregnancy BMI, smoking, pre-existing diseases, and conditions in pregnancy, with adjustment for confounding factors. MAIN OUTCOME MEASURES: Birth defects classified by International Classification of Diseases (ninth revision) and British Paediatric Association (ICD9-BPA) codes. RESULTS: There were 2211 IVF, 1399 ICSI, and 301 060 naturally conceived births. The unadjusted prevalence of any birth defect was 7.1, 9.9, and 5.7% in the IVF, ICSI, and natural conception groups, respectively. As expected, the risk of birth defects increased with maternal age among the natural conceptions. In contrast, for IVF and ICSI combined, relative to natural conceptions, births to women aged ≤29 years had a higher risk (adjusted odds ratio, aOR 1.42; 95% confidence interval, 95% CI 1.04-1.94), births to women aged 35-39 years had no difference in risk (aOR 1.01; 95% CI 0.74-1.37), and births to women aged ≥40 years had a lower risk of defects (aOR 0.45; 95% CI 0.22-0.92). Defects were also elevated for nulliparity, anaemia, and urinary tract infection in births after ICSI, but not after IVF. CONCLUSIONS: The usual age-birth defect relationship is reversed in births after IVF and ICSI, and the associations for other maternal factors and defects vary between IVF and ICSI. TWEETABLE ABSTRACT: Risk of birth defects in women over 40 years is lower after infertility treatment than for natural conceptions.

The effect of temperature on different Salmonella serotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia.

Changing trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues. Salmonella spp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature and Salmonella spp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months on Salmonella spp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. Daily Salmonella spp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008-1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008-1·061) to 4·4% (IRR 1·044, 95% CI 1·024-1·064). We observed increased cases of S. Typhimurium PT9 and S. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on different Salmonella spp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather.

Growth trajectories in early childhood, their relationship with antenatal and postnatal factors, and development of obesity by age 9 years: results from an Australian birth cohort study.

BACKGROUND: In an era where around one in four children in the United Kingdom, the United States, and Australia are overweight or obese, the development of obesity in early life needs to be better understood. We aimed to identify groups of children with distinct trajectories of growth in infancy and early childhood, to examine any association between these trajectories and body size at age 9, and to assess the relative influence of antenatal and postnatal exposures on growth trajectories. DESIGN: Prospective Australian birth cohort study. SUBJECTS AND METHODS: In total, 557 children with serial height and weight measurements from birth to 9 years were included in the study. Latent class growth models were used to derive distinct groups of growth trajectories from birth to age 3½ years. Multivariable logistic regression models were used to explore antenatal and postnatal predictors of growth trajectory groups, and multivariable linear and logistic regression models were used to examine the relationships between growth trajectory groups and body size at age 9 years. RESULTS: We identified four discrete growth trajectories from birth to age 3½ years, characterised as low, intermediate, high, or accelerating growth. Relative to the intermediate growth group, the low group had reduced z-body mass index (BMI) (-0.75 s.d.; 95% confidence interval (CI) -1.02, -0.47), and the high and accelerating groups were associated with increased body size at age 9 years (high: z-BMI 0.70 s.d.; 95% CI 0.49, 0.62; accelerating: z-BMI 1.64 s.d.; 95% CI 1.16, 2.11). Of the antenatal and postnatal exposures considered, the most important differentiating factor was maternal obesity in early pregnancy, associated with a near quadrupling of risk of membership of the accelerating growth trajectory group compared with the intermediate growth group (odds ratio (OR) 3.72; 95% CI 1.15, 12.05). CONCLUSIONS: Efforts to prevent childhood obesity may need to be embedded within population-wide strategies that also pay attention to healthy weight for women in their reproductive years.

Maternal body size prior to pregnancy, gestational diabetes and weight gain: associations with insulin resistance in children at 9-10 years.

AIMS: To investigate whether maternal body size pre-pregnancy, gestational diabetes and weight gain are independently associated with subsequent insulin resistance in children; and to examine the potential mediating role of child's body size in any associations. METHODS: At 9-10 years, 443 children took part in a follow-up of a prospective cohort. Of those, 163 children elected to provide a fasting blood sample and child insulin resistance was estimated by homeostasis model assessment. Generalized linear models with log link function and Gaussian family were used to assess associations with antenatal exposures. Potential confounders were considered as well as the role of the child's size. RESULTS: Prior to pregnancy, 23% of mothers were overweight and another 17% obese. All women were screened for gestational diabetes, with 6% diagnosed. On average, women gained an estimated 14 kg during pregnancy. Gestational diabetes was positively associated with child insulin resistance. In addition, maternal pre-pregnancy body mass index (BMI) was associated with child insulin resistance in a non-linear manner: a positive, progressive association was observed until BMI of 30 kg/m² was reached, but not thereafter. Estimated gestational weight gain was not associated with child insulin resistance. These findings were not accounted for by size of the child at birth or at 9-10 years. CONCLUSIONS: Maternal body size prior to pregnancy is positively associated with increases in child insulin resistance, at least until the 'obese' category is reached. This is independent of gestational diabetes and not mediated by body size of the child, suggesting genetic and/or developmental programming origins.

Sleep disturbances in a community-based sample of women with polycystic ovary syndrome.

STUDY QUESTION: Is there an excess of sleep disturbances in women with polycystic ovary syndrome (PCOS) in a community-based sample? STUDY ANSWER: Sleep disturbances are almost twice as common in women with PCOS compared with women of similar age without PCOS, with the association slightly accounted for by body weight and, to a greater extent, by depressive symptoms. WHAT IS KNOWN ALREADY: There is an excess of sleep-disordered breathing in clinical samples of women with PCOS, after accounting for their profile of body weight. Poor sleep patterns increase insulin resistance and thus may exacerbate PCOS symptoms and longer-term risk of metabolic disease. STUDY DESIGN, SIZE, DURATION: A cross-sectional study of 724 women, comprising 74% of a cohort study established retrospectively when women were around age 30 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: Comparisons were made between 87 women with PCOS, diagnosed using the Rotterdam criteria, and 637 women without this diagnosis in Adelaide, South Australia. Differences in sleep disturbances, assessed using a modified version of the Jenkins questionnaire, were investigated using ordered logistic regression. MAIN RESULTS AND THE ROLE OF CHANCE: Sleep disturbances were twice as common in women with PCOS compared with those without. Specifically, PCOS was associated with increasing occurrence of difficulty falling asleep (odds ratio (OR) 1.94, 95% confidence interval (CI) 1.28-2.95); this association was attenuated but still statistically significant after accounting for BMI and depressive symptoms. Increasing occurrence of difficulty maintaining sleep (OR 1.92 95% CI 1.12-3.31) was mediated by obesity and depressive symptoms, together. Other factors did not change these findings. LIMITATIONS, REASONS FOR CAUTION: The cross-sectional nature of the study means that the direction of associations between PCOS and sleep disturbances is unclear, although bi-directionality for the mediators is likely based on data in the wider literature. WIDER IMPLICATIONS OF THE FINDINGS: Our results indicate that assessment and management of both sleep and mental health problems in women with PCOS should be undertaken. Longitudinal data would be valuable to see how poor sleep affects longer-term health profiles.

Is precarious employment associated with women remaining childless until age 35 years? Results from an Australian birth cohort study.

STUDY QUESTION: Does time in casual employment (while not studying full time) affect the likelihood of a woman having a child by age 35? SUMMARY ANSWER: Duration of time spent in casual employment is associated with an increased likelihood of childlessness at age 35 years, irrespective of socio-economic background as indicated by educational level. WHAT IS KNOWN ALREADY: Precarious employment conditions have become increasingly prevalent in recent decades in Western countries. The relationship between precarious employment conditions and age at first childbirth has been examined in several European countries with varying results. STUDY DESIGN, SIZE, DURATION: A retrospective cross-sectional component (n = 663) was added to an existing study based on a cohort of women born during 1973-1975. An event history calendar instrument was used to obtain data regarding a range of life domains over a 20-year period. PARTICIPANTS/MATERIALS, SETTING, METHODS: Using data from the Life Journeys of Young Women Project carried out in Adelaide, South Australia, Cox proportional hazards models were applied to investigate the research questions. MAIN RESULTS AND THE ROLE OF CHANCE: The likelihood of childbirth by around age 35 was reduced for every year spent in casual employment, irrespective of socioeconomic status, partner's education and parents' birthplace. The likelihood was reduced by 8, 23 and 35% for 1, 3 and 5 years spent in casual employment, respectively. LIMITATIONS, REASONS FOR CAUTION: Women with longer employment histories (and greater age at first birth) had more opportunities for errors in recall, but it is unlikely that such errors were systematic and led to bias in the results. While we included variables reflecting partner's education and length of time with a live-in partner, partner's employment histories were not taken into account. WIDER IMPLICATIONS OF THE FINDINGS: Duration of time spent in casual employment is associated with an increased likelihood of childlessness at age 35 years, and this association is present across the spectrum of socioeconomic status. We suggest that upstream labour market reforms could be considered in order to reduce barriers to childbearing.

Growth in early life and the development of obesity by age 9 years: are there critical periods and a role for an early life stressor?

OBJECTIVE: Rapid growth, possibly occurring in critical periods in early life, may be important for the development of obesity. It is unknown whether this is influenced by postnatal exposures such as age-relevant sources of stress. Frequent house moves may be one such stressor. We aimed to examine if there is a period of growth in early life critical for the development of child obesity by age 9 years and assess the role of house moves in modifying any relationships between early life growth and obesity at age 9 years. DESIGN: Prospective Australian birth cohort study. SUBJECTS: In all, 392 children with serial body size measurements from birth to age 9 years. METHODS: Standardized body mass index (z-BMI) was available for six time points (spanning birth to 3½ years), and the total number of house moves between birth and 3½ years. The outcomes considered were z-BMI and % body fat (%BF) at age 9 years. Linear regression models were used to estimate the effects of serial measurements of z-BMI and number of house moves on the outcomes. RESULTS: Life-course plots showed that z-BMI at 3½ years was a statistically significant predictor of z-BMI at 9 years (ß=0.80; standard error (s.e.), 0.04), whereas z-BMI at 9 months (ß=-1.13; s.e., 0.40) and 3½ years (ß=4.82; s.e., 0.42) were significant predictors of %BF at age 9 years. There were statistically significant interactions between the number of house moves and change in z-BMI between 9 and 12 months, such that ≥ 3 house moves in early life amplified the detrimental effects of earlier rapid growth on both body size and composition at age 9 years. CONCLUSION: In the absence of evidence for a single critical period, efforts to prevent overweight and obesity are required throughout childhood. In addition, modifiable postnatal stressors may exacerbate effects of early growth on obesity in later childhood.

Birthweight and thinness at birth independently predict symptoms of polycystic ovary syndrome in adulthood.

BACKGROUND: The aetiology of polycystic ovary syndrome (PCOS) is unknown and contested. While it has been suggested that PCOS could have origins in perturbed development, epidemiological findings have been inconclusive. We aimed to examine potential fetal origins of PCOS. METHODS: A retrospective birth cohort of 948 singleton female babies born at one hospital in South Australia in 1973-1975 was assembled. Birth characteristics were obtained from hospital records and PCOS symptoms were identified through interview and clinical examination when women were ~30 years old. Based on the combination of PCOS symptoms, women formed seven outcome groups. A multinomial logistic regression analysis was used to investigate associations between birth characteristics and these outcome groups. RESULTS: After adjusting for gestational age, two distinct birth characteristics were associated with two PCOS symptom groups. Each 100 g increase in birthweight increased the risk of hyperandrogenism (as a single symptom) in adulthood by 5% [relative risk ratio: 1.05, 95% confidence interval (CI): 1.01-1.09]. In contrast, each one unit increase in the ponderal index at birth decreased the risk of all three key PCOS symptoms (hyperandrogenism, menstrual dysfunction and polycystic ovaries) by 21% (0.79, 95% CI: 0.66-0.93). CONCLUSIONS: These results suggest two discrete fetal programming pathways (related to high birthweight and to thinness at birth) are operating. Our findings point to differing aetiologies for symptom clusters, and inform the debate over symptoms that best represent the disorder.

Parental work schedules and child overweight and obesity.

OBJECTIVE: Studies in school-age children have consistently shown a positive association between maternal paid work hours and child obesity. However, there is conflicting evidence about the impact of maternal work hours scheduled at nonstandard times (for example, evenings, nights or weekends), and no previous examination of paternal work schedules and child weight. We examined the associations between maternal, paternal and combined parental paid work schedules and overweight/obesity in children at age 9 years. METHODS: Data were analysed from the most recent follow-up of 9-year-old children (n=434) in an Australian birth cohort study. Children were measured and classified as overweight/obese using the International Obesity Taskforce body mass index cutoff points. Current working conditions of parents were obtained from a structured interview with the primary caregiver. Logistic regression analyses were used to investigate the effect of parental work schedules on child overweight/obesity with adjustment for a range of sociodemographic and household factors associated with parental employment and child weight. RESULTS: At 9 years of age, 99 children (22.8%) were overweight or obese. When parental work schedules were examined separately, child overweight/obesity was significantly associated with paternal nonstandard work schedules (adjusted odds ratio (OR) 1.97, 95% confidence interval (CI) 1.08-3.61). There was no association with any type of maternal work schedule. We also found an association between child overweight/obesity and circumstances in which both parents worked nonstandard schedules; however, this was of borderline statistical significance in the adjusted models (adjusted OR 2.26, 95% CI 0.99-5.16). CONCLUSION: Work hours scheduled at nonstandard times, when worked by the father or both parents, were associated with child overweight and obesity. These findings indicate the potential importance of fathers' paid work arrangements for child overweight/obesity, which until recently has largely been ignored.

Self-management and peer support among people with arthritis on a hospital joint replacement waiting list: a randomised controlled trial.

INTRODUCTION: To evaluate the efficacy of a self-management support program including a 6 week self-management course, individualised phone support and goal setting in osteoarthritis patients on a waiting list for arthroplasty surgery. METHOD: Randomised controlled trial of 152 public hospital outpatients awaiting hip or knee replacement surgery who were not classified as requiring urgent surgery. Participants were randomised to a self-management program or to usual care. The primary outcome was change in the Health Education Intervention Questionnaire (HeiQ) from randomisation to 6 month follow-up. Quality of life and depressive symptoms were also measured. Changes in pain and function were assessed using the Western Ontario and McMaster Universities (WOMAC) Arthritis Index. RESULTS: At 6 month follow-up, health-directed behaviour was significantly greater in the intervention [mean 4.29, 95% confidence interval (CI) 3.99-4.58] than the control (mean 3.81, 95% CI 3.52-4.09; P=0.017). There was also a significant effect on skill and technique acquisition for the intervention (mean 4.37, 95% CI 4.19-4.55) in comparison to control (mean 4.11, 95% CI 3.93-4.29; P=0.036). There was no significant effect of the intervention on the remaining HeiQ subscales, WOMAC pain or disability, quality of life or depressive symptoms. DISCUSSION: The arthritis self-management program improved health-directed behaviours, skill acquisition and stiffness in patients on a joint replacement waiting list, although the observed effects were of modest size (Cohen's d between 0.36 and 0.42). There was no significant effect on pain, function or quality of life in the short term. Self-management programs can assist in maintaining health behaviours (particularly walking) in this patient group. Further research is needed to assess their impact on quality of life and over longer periods.

Establishment of and first 20 months of operating an outreach geriatric clinic in a regional centre.

INTRODUCTION: Providing geriatric assessments to older people residing in rural or remote areas is a challenge due to the complexities of distance and a declining medical workforce. This study aimed to develop a feasible model of service delivery in a rural area, delivering specialised falls and memory clinics similar to those available in the metropolitan area. At the end of the first 20 months we evaluated the service in terms of patient access and the satisfaction of the local health care providers. METHODS: A meeting was held with key stakeholders to identify existing service provision in the region, and to determine which services were needed. Clinic attendance and information on services provided by the clinic were collected. Questionnaires regarding clinic performance were sent to health-care providers in the region. RESULTS: The stakeholder meeting identified communication, collaboration and continuing education as the main services required of the clinic. The clinic model included a specialist geriatrician and an extended practice nurse specialising in aged care. Between May 2003 and Dec 2004, 115 people were assessed by the extended practice nurse. Interventions relating to falls and cognition were accessed by clients. Time from referral to seeing a specialist and failure to attend rates were comparable to rates seen in the metropolitan clinics. All heath-care providers who responded to the survey found the service useful. CONCLUSION: Our clinic model is a possible mechanism for delivering ambulatory aged care services to rural and remote regions. This model of care did not improve access or shorten waiting times for attendees. Future models of specialised rural care need to explore innovative workforce strategies to improve access.

Demographic, health, cognitive, and sensory variables as predictors of mortality in very old adults.

Cognitive and sensorimotor predictors of mortality were examined in the Australian Longitudinal Study of Ageing, controlling for demographic and health variables. A stratified random sample of 1,947 males and females aged 70 and older were interviewed, and 1,500 were assessed on measures of health, memory. verbal ability, processing speed, vision, hearing, and grip strength in 1992 and 1994. Analyses of incident rate ratios for mortality over 4- and 6-year periods were conducted using Cox hierarchical regression analyses. Results showed that poor performance on nearly all cognitive variables was associated with mortality, but many of these effects were explained by measures of self-rated health and disease. Significant decline in hearing and cognitive performance also predicted mortality as did incomplete data at Wave 1. Results suggest that poor cognitive performance and cognitive decline in very old adults reflect both biological aging and disease processes.

Effects of diaspirin cross-linked hemoglobin on motor function of the duodenum and biliary system in the Australian brush-tailed possum in vivo.

Chemically altered hemoglobin-based oxygen carriers have been developed as prototype blood substitutes. Such molecules may affect numerous biological processes, since free hemoglobin scavenges nitric oxide (NO). Diaspirin cross-linked hemoglobin (DCLHb) is a chemically cross-linked molecule, which has a pressor effect on blood pressure, mainly mediated by NO scavenging. However, the effects of DCLHb on the gastrointestinal and biliary motility have not been reported. This study was conducted to investigate the effects of DCLHb on the duodenal and biliary motility and determine if the underlying mechanism involves a NO pathway. Blood pressure, duodenal, sphincter of Oddi and gallbladder motility and trans-sphincteric flow were recorded in anesthetized Australian Brush-tailed possums. The effects of intravenously administered DCLHb (10% solution) or oncotically matched human serum albumin (HSA) solution on these parameters were investigated. To determine the involvement of a NO-mediated pathway in these effects, animals were pretreated with N(omega)-nitro-L-arginine methyl ester (L-NAME) before DCLHb or HSA was given. DCLHb increased blood pressure and duodenal contraction frequency and slowed trans-sphincteric flow compared with the HSA control. The effects of DCLHb on blood pressure and trans-sphincteric flow were immediate and transient, whereas the effect on duodenal contraction frequency was delayed and long-lived. Pretreatment with L-NAME alone increased blood pressure and duodenal contraction frequency and slowed trans-sphincteric flow. DCLHb-induced changes were not evident in the presence of L-NAME. These findings suggest that DCLHb affects duodenal and trans-sphincteric flow predominantly by NO scavenging.

Exercise profile and subsequent mortality in an elderly Australian population.

Although the importance of exercise as a public health issue is increasingly recognised, little attention has been paid to exercise in very old people. We examined exercise patterns in 1788 subjects aged 70 years and over who were participating in the Australian Longitudinal Study of Ageing. In the two weeks before interview, 39 per cent of subjects had taken no exercise and only four per cent had exercised vigorously. When compared with those who took no exercise, exercisers were more likely to be male and younger, to self-report better health, to be former smokers and regular alcohol users. Mortality rates at two years follow-up were inversely related to the level of exercise at baseline. This research indicates that exercise is important for the very old as well as younger groups.

Inheritance and linkage of isozyme loci in almond.

The segregation of seven isozyme marker genes was investigated using eight controlled crosses in almond. The cultivar 'Nonpareil' was the maternal parent in all crosses. Pollination was achieved using eight different cultivars, and a total of 3200 individual kernels were assessed. For each isozyme the goodness-of-fit test was used to test for departure from the expected frequencies assuming Mendelian inheritance. Given a higher than expected number of significant results for individual isozymes, independent segregation between pairs of isozymes was tested using the chi-square statistic on the resulting two-way contingency tables. In all crosses a highly significant association (P value< 0.001) was observed between (1) the AAT- 1 and IDH isozymes loci and (2) the LAP-1 and PGM-2 isozymes loci, which leads to the conclusion that the respective isozyme pairs are linked.In addition, a significant association (P value < 0.001) was observed between LAP-1 and GPI-2 when the pollen sources were 'Fritz', 'Mission', or 'Price', but this could not be tested for the remaining five pollen sources, 'Carmel', 'Grant', 'Keane', 'Ne plus Ultra', 'Peerless', because they are homozygous at these loci. If LAP-1 is linked with GPI-2 and PGM-2, it might be expected that we should find evidence of linkage between GPI-2 and PGM-2. The lack of a significant association between these two isozymes suggests that LAP-1 is located centrally on the chromosome. These three pairs of linked loci are the first to be reported in almond.