Has Chlamydia trachomatis prevalence in young women in England, Scotland and Wales changed? Evidence from national probability surveys.

We evaluate the utility of the National Surveys of Attitudes and Sexual Lifestyles (Natsal) undertaken in 2000 and 2010, before and after the introduction of the National Chlamydia Screening Programme, as an evidence source for estimating the change in prevalence of Chlamydia trachomatis (CT) in England, Scotland and Wales. Both the 2000 and 2010 surveys tested urine samples for CT by Nucleic Acid Amplification Tests (NAATs). We examined the sources of uncertainty in estimates of CT prevalence change, including sample size and adjustments for test sensitivity and specificity, survey non-response and informative non-response. In 2000, the unadjusted CT prevalence was 4.22% in women aged 18-24 years; in 2010, CT prevalence was 3.92%, a non-significant absolute difference of 0.30 percentage points (95% credible interval -2.8 to 2.0). In addition to uncertainty due to small sample size, estimates were sensitive to specificity, survey non-response or informative non-response, such that plausible changes in any one of these would be enough to either reverse or double any likely change in prevalence. Alternative ways of monitoring changes in CT incidence and prevalence over time are discussed.

Variation in the recall of socially rewarding information and depressive symptom severity: a prospective cohort study.

OBJECTIVE: To test the association between recall for socially rewarding (positive) and/or socially critical (negative) information and depressive symptoms. METHOD: Cohort study of people who had visited UK primary care in the past year reporting depressive symptoms (N = 558, 69% female). Positive and negative recall was assessed at three time-points, 2 weeks apart, using a computerised task. Depressive symptoms were assessed at four time-points using the Beck Depression Inventory (BDI). Analyses were conducted using multilevel models. RESULTS: Concurrently we found evidence that, for every increase in two positive words recalled, depressive symptoms reduced by 0.6 (95% CI -1.0 to -0.2) BDI points. This association was not affected by adjustment for confounders. There was no evidence of an association between negative recall and depressive symptoms (-0.1, 95% CI -0.5 to 0.3). Longitudinally, we found more evidence that positive recall was associated with reduced depressive symptoms than vice versa. CONCLUSION: People with more severe depressive symptoms recall less positive information, even if their recall of negative information is unaltered. Clinicians could put more emphasis on encouraging patients to recall positive, socially rewarding information, rather than trying to change negative interpretations of events that have already occurred.