Design Parallel group cohort study embedded in a randomised controlled trial.

Setting 15 practices (10 screening, 5 control) in the ADDITION (Cambridge) trial.

Participants 5334 adults (aged 40-69) in the top quarter for risk of having undiagnosed type 2 diabetes (964 controls and 4370 screening attenders).

Main outcome measures Perceived personal and comparative risk of diabetes, intentions for behavioural change, and self rated health measured after an initial random blood glucose test and at 3-6 and 12-15 months later (equivalent time points for controls).

Results A linear mixed effects model with control for clustering by practice found no significant differences between controls and people who screened negative for diabetes in perceived personal risk, behavioural intentions, or self rated health after the first appointment or at 3-6 months or 12-15 months later. After the initial test, people who screened negative reported significantly (but slightly) lower perceived comparative risk (mean difference –0.16, 95% confidence interval –0.30 to –0.02; P=0.04) than the control group at the equivalent time point; no differences were evident at 3-6 and 12-15 months.

Conclusions A negative test result at diabetes screening does not seem to promote false reassurance, whether this is expressed as lower perceived risk, lower intentions for health related behavioural change, or higher self rated health. Implementing a widespread programme of primary care based stepwise screening for type 2 diabetes is unlikely to cause an adverse shift in the population distribution of plasma glucose and cardiovascular risk resulting from an increase in unhealthy behaviours arising from false reassurance among people who screen negative.

Trial registration Current controlled trials ISRCTN99175498.

Design Population based, prospective cohort study with follow-up over three years.

Setting New South Wales, Australia.

Participants Men with localised prostate cancer were eligible if aged less than 70 years, diagnosed between October 2000 and October 2002, and notified to the New South Wales central cancer registry. Controls were randomly selected from the New South Wales electoral roll and matched to cases by age and postcode.

Main outcome measures General health specific and disease specific function up to three years after diagnosis, according to the 12 item short form health survey and the University of California, Los Angeles prostate cancer index.

Results 1642 (64%) cases and 495 (63%) eligible and contacted controls took part in the study. After adjustment for confounders, all active treatment groups had low odds of having better sexual function than controls, in particular men on androgen deprivation therapy (adjusted odds ratio (OR) 0.02, 95% CI 0.01 to 0.07). Men treated surgically reported the worst urinary function (adjusted OR 0.17, 95% CI 0.13 to 0.22). Bowel function was poorest in cases who had external beam radiotherapy (adjusted OR 0.44, 95% CI 0.30 to 0.64). General physical and mental health scores were similar across treatment groups, but poorest in men who had androgen deprivation therapy.

Conclusions The various treatments for localised prostate cancer each have persistent effects on quality of life. Sexual dysfunction three years after diagnosis was common in all treatment groups, whereas poor urinary function was less common. Bowel function was most compromised in those who had external beam radiotherapy. Men with prostate cancer and the clinicians who treat them should be aware of the effects of treatment on quality of life, and weigh them up against the patient’s age and the risk of progression of prostate cancer if untreated to make informed decisions about treatment.

Design Prospective birth cohort study with data collected between 2003 and 2007.

Setting Original recruitment in 1991-2 of 14 541 pregnant women living in the former County of Avon (United Kingdom).

Participants At age 12, 11 952 children were invited to attend the research clinic. Of these, 7159 attended, and 4150 (1964 boys, 2186 girls) provided sufficient data on exposure, outcome, and confounding variables.

Main outcome measure Fat mass at age 14, measured by dual emission x ray absorptiometry, associated with physical activity at age 12, measured by accelerometry.

Results Prospective associations of fat mass at age 14 (outcome) with physical activity at age 12 (exposure) were strong for both total activity (accelerometer counts/min) and for daily amount of moderate-vigorous physical activity (min/day). An extra 15 minutes of moderate-vigorous physical activity per day at age 12 was associated with lower fat mass at age 14 in boys (by 11.9% (95% confidence interval 9.5% to 14.3%)) and girls (by 9.8% (6.7% to 12.8%)). The proportion of physical activity due to moderate-vigorous physical activity was between 20% and 30% in boys and girls at the two ages.

Conclusions Higher levels of physical activity, in particular activity of moderate to higher intensities, are prospectively associated with lower levels of fat mass in early adolescence. Interventions to raise levels of physical activity in children are likely to be important in the fight against obesity.