Epidemiologic merit of obese-years, the combination of degree and duration of obesity

This study aims to test the effect of combining the degree and the duration of obesity into a single variable-obese-years-and to examine whether obese-years is a better predictor of the risk of diabetes than simply body mass index (BMI) or duration of obesity. Of the original cohort of the Framingham Heart Study, 5,036 participants were followed up every 2 years for up to 48 years (from 1948). The variable, obese-years, was defined by multiplying for each participant the number of BMI units above 30 kg/m(2) by the number of years lived at that BMI. Associations with diabetes were analyzed by using time-dependent Cox proportional hazards regression models adjusted for potential confounders. The incidence of type-2 diabetes increased as the number of obese-years increased, with adjusted hazard ratios of 1.07 (95% confidence interval: 1.06, 1.09) per additional 10 obese-years. The dose-response relation between diabetes incidence and obese-years varied by sex and smoking status. The Akaike Information Criterion was lowest in the model containing obese-years compared with models containing either the degree or duration of obesity alone. A construct of obese-years is strongly associated with risk of diabetes and could be a better indicator of the health risks associated with increasing body weight than BMI or duration of obesity alone.

The duration of obesity and the risk of type-2 diabetes

Objective The evidence for the association between obesity and the risk of type 2 diabetes has been derived mainly from the analysis of the degree of obesity. The role of the duration of obesity as an independent risk has not been fully explored. The objective of the present study was to investigate the association between the duration of obesity and the risk of type 2 diabetes.

Design Prospective cohort study.

Setting The Framingham Heart Study (FHS), follow-up from 1948 to 1998.

Subjects A total of 1256 FHS participants who were free from type 2 diabetes at baseline, but were obese on at least two consecutive of the study’s twenty-four biennial examinations, were included. Type 2 diabetes status was collected throughout the 48 years of follow-up of the study. The relationship between duration of obesity and type 2 diabetes was analysed using time-dependent Cox models, adjusting for a number of covariates.

Results The unadjusted hazard ratio (HR) for the risk of type 2 diabetes for men was 1·13 (95 % CI 1·09, 1·17) and for women was 1·12 (95 % CI 1·08, 1·16) per additional 2-year increase in the duration of obesity. Adjustment for sociodemographic variables, family history of diabetes, health behaviour and physical activity made little difference to these HR. For women the evidence of a dose–response relationship was less clear than for men, particularly for women with an older age at obesity onset.

Conclusions The duration of obesity is a relevant risk factor for type 2 diabetes, independent of the degree of BMI.

Duration and persistence in multidimensional deprivation : methodology and Australian application

This article extends the recent literature on static multidimensional deprivation to propose dynamic deprivation measures that incorporate both the persistence and duration of deprivation across multiple dimensions. The article then illustrates the usefulness of the extension by applying it to Australian panel data for the recent period, 2001–2008. The empirical application exploits the subgroup decomposability of the deprivation measures to identify the subgroups that are more deprived than others. The proposed measure is also decomposable by dimensions and is used to identify the dimensions where deprivation is more persistent. The comparison between the subgroups shows that the divide between homeowners and non-homeowners is one of the sharpest, with the latter suffering much more deprivation than the former. The results are robust to alternative schemes for weighting and aggregating the dimensions as well as to the choice of model parameters.

Increased positive thought disorder with illness duration in patients with schizophrenia

It is unclear whether the severity of positive formal thought disorder, a core clinical feature of schizophrenia, is stable or worsening through the chronic course of the illness. The neurocognitive basis for positive thought disorder also remains unclear. The aim of the present paper was to examine the relationship between thought disorder as measured by the Thought Disorder Index (TDI) and duration of illness and neuropsychological indices in 79 patients with schizophrenia. TDI scores increased in proportion to illness duration. TDI scores were not associated with verbal memory or executive functioning. These results indicate an ongoing worsening of positive thought disorder through the course of illness in schizophrenia.

Biochemical responses of earthworm Eisenia fetida exposed to cadmium-contaminated soil with long duration

The biochemical responses of the earthworms, Eisenia fetida, exposed to a series of Cd concentrations (0.00, 1.25, 2.50, 5.00 and 10.00 mg Cd2+ kg−1 soil) for up to 8 weeks were investigated, aiming to evaluate the sublethal effects of Cd with long exposure and to explore the potential for applying these responses as biomarkers to indicate the Cd-contaminated soil. The following biochemical parameters were determined: cytochrome P450 (CYP) contents and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-s-transferase (GST). Cadmium concentrations in all earthworms were apparently accumulated in 4 weeks, and showed minor changes in weeks 6–8 compared to the first 4 weeks. CYP presented a significant elevation in 2–4 weeks and a decline in 6–8 weeks in each treated group. The activities of SOD and CAT showed an obvious increase with exposure of 6–8 weeks while their levels were not affected in 4 weeks in each treated group. GST activity revealed significant activation starting from week 4. This study confirmed the significance of applying a suite of biomarkers rather than a selective choice to assess the impact of pollutants on organisms. It also indicated that the observed effects were more dependent upon exposure duration than dose.

Sexual practices and the duration of last heterosexual encounter : findings from the Australian longitudinal study of health and relationships

This study investigated the association between sexual practices and duration of a sexual encounter. Using data from a population-based computer-assisted telephone survey of 8,656 Australians aged 16 to 64 years, four distinct patterns of sexual practices among respondents were found: “basic sexual encounter” (involving mainly kissing, cuddling, stroking one's partner and being stroked, and vaginal intercourse), “basic sexual encounter plus oral sex,” “all assessed sexual practices” (all sexual behaviors included in the survey), and “mainly vaginal intercourse” (characterized by lower levels of kissing, cuddling, and stroking). For both men and women, respondents classified in the basic sexual encounter plus oral sex, and all assessed sexual practices clusters reported significantly longer durations than those in the basic sexual encounter group, whereas respondents in the mainly vaginal intercourse cluster reported shorter durations. These differences were found even after allowing for demographic differences in sexual duration—specifically, age and partner type of the most recent opposite-sex partner. These findings add to the understanding of what typically happens in a sexual encounter. Overall, longer sexual encounters appear to be associated with the inclusion of the least common sexual practices—namely, oral sex and self-stimulation.

The implications of lung-regulated buoyancy control for dive depth and duration

Among air-breathing divers, control of buoyancy through lung volume regulation may be most highly developed in marine turtles. In short, the turtle lung may serve a dual role as both an oxygen store and in buoyancy control. A simple model is developed to show that, for turtles diving up to the maximum depth at which they can still use their lungs to attain neutral buoyancy, the total oxygen store will increase greatly with dive depth, and hence a corresponding increase in dive duration is predicted. Time–depth recorders attached to free-living green turtles (Chelonia mydas) at Ascension Island confirmed a marked increase in dive duration with depth, with the gradient of this relationship being >10 times that seen in diving birds and mammals. Consistent with the prediction that the lungs serve a dual role, we found that, when lead weights were added to some turtles to increase their specific gravity, the mean depth of dives decreased, but for dives to the same depth, weighted animals dived for longer. The depth distribution of green turtles seems to be generally constrained by the maximum depth at which they can still attain close to neutral buoyancy.

Duration of unemployment and suicide in Australia over the period 1985–2006: an ecological investigation by sex and age during rising versus declining national unemployment rates

Background The relationship between unemployment and suicide may be sensitive to demographic factors, national unemployment rates, and length of time without employment. This study investigated these factors in relation to suicide in Australia for the period 1985–2006, in an ecological study. Methods The outcome variable was annual suicide rate by age group, sex and the eight states and territories over 22 years of observation (total observations=1760). The main predictor variable was the average duration of unemployment in the population, categorised into three time periods (<2 weeks, 2–4 weeks, >4 weeks). Poisson regression models were used to investigate the relationship between duration of unemployment and suicide over the years 1985–2006 in a series of cross-sectional analyses. Interaction analyses indicated significant differences during periods of declining or increasing labour market opportunity and by age group. Results During periods of declining unemployment rates in the country, longer durations of unemployment were associated with higher male suicide rates. During periods of increasing unemployment in the country, longer unemployment duration was associated with lower male suicide rates. Effect modification was also apparent by age-group, with stronger associations between unemployment duration and male suicide evident in those aged 25–34 and 55–64, and weaker associations in those aged 15–24 and 44–54 years. Longer length of unemployment was not associated with an increase in female suicide rates. Conclusions The labour market opportunities in Australia modified the effect of duration of unemployment on suicide, and the effect was more prominent in men and older age groups. This may reflect social norms and acceptability about unemployment, as well as life-stage influences associated with transitions into and out of the labour market.

A longitudinal study of the effect of psychosocial factors on exclusive breastfeeding duration

Objective
to examine the effect of psychosocial factors on exclusive breastfeeding duration to six months postpartum

Design
longitudinal, prospective questionnaire based study.

Setting
participants were recruited from a publically funded antenatal clinic located in the western metropolitan region of Melbourne, Victoria, Australia and asked to complete questionnaires at three time points; 32 weeks pregnancy, two months postpartum and six months postpartum.

Participants
the participants were 125 pregnant women aged 22–44 years.

Measurements and findings
psychosocial variables such as breastfeeding self-efficacy, body attitude, psychological adjustment, attitude towards pregnancy, intention, confidence and motivation to exclusively breastfeed and importance of exclusive breastfeeding were assessed using a range of psychometrically validated tools. Exclusive breastfeeding behaviour up to six months postpartum was also measured. At 32 weeks gestation a woman׳s confidence to achieve exclusive breastfeeding was a direct predictor of exclusive breastfeeding duration to six months postpartum. At two months postpartum, psychological adjustment and breastfeeding self-efficacy were predictive of exclusive breastfeeding duration. Finally, at six months postpartum, psychological adjustment, breastfeeding self-efficacy, confidence to maintain and feeling fat were directly predictive of exclusive breastfeeding duration.