Objective. To perform a systematic review of the global prevalence of low back pain, and to examine the influence that case definition, prevalence period, and other variables have on prevalence.Methods. We conduced a new systematic review of the global prevalence of low back pain that included general population studies published between 1980 and 2009. A total of 165 studies from 54 countries were identified. Of these, 64% had been published since the last comparable review.Results. Low back pain was shown to be a major problem throughout the world, with the highest prevalence among female individuals and those aged 40-80 years. After adjusting for methodologic variation, the mean ؎ SEM point prevalence was estimated to be 11.9 ؎ 2.0%, and the 1-month prevalence was estimated to be 23.2 ؎ 2.9%.Conclusion. As the population ages, the global number of individuals with low back pain is likely to increase substantially over the coming decades. Investigators are encouraged to adopt recent recommendations for a standard definition of low back pain and to consult a recently developed tool for assessing the risk of bias of prevalence studies.

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Melanoma may be preventable by regular sunscreen use in adults.

The relationships between severity, chronicity, and timing of maternal depressive symptoms and child outcomes were examined in a cohort of 4,953 children. Mothers provided selfreports of depressive symptoms during pregnancy, immediately postpartum, and when the child was 6 months old and 5 years old. At the age 5 follow-up, mothers reported on children's behavior and children completed a receptive vocabulary test. Results suggest that both the severity and the chronicity of maternal depressive symptoms are related to more behavior problems and lower vocabulary scores in children. The interaction of severity and chronicity of maternal depressive symptoms was significantly related to higher levels of child behavior problems. Timing of maternal symptoms was not significantly related to child vocabulary scores, but more recent reports of maternal depressive symptoms were associated with higher rates of child behavior problems.Many studies have documented the association between maternal depression and adverse outcomes in children. Studies with clinical samples of depressed parents, focused primarily on mothers, have shown elevated rates of depression in children as well as anxiety and disruptive behavior disorders (reviewed in Downey & Coyne, 1990;Hammen, 1999). Studies with community samples of women with self-reported symptoms of depression have also shown adverse outcomes in children. These latter studies included infants, toddlers, and children of varying ages, and virtually all measures of the children's affect and behaviors showed evidence of maladaptive reactions to their mothers' dysphoria (reviewed in Downey & Coyne;Gelfand & Teti, 1990).The consistency of detrimental effects across numerous samples and methodologies has doubtless suggested that maternal depressive symptoms invariably have a negative impact on children's behavior. However, most of the studies have been cross-sectional in design, and they provide little information about the nature of maternal depression and how often it leads to problems for children. Depression is extremely heterogeneous in its manifestations, ranging from mild and transitory mood distress that is entirely normal to persisting and severe

This article examines an improved alternative to the random effects (RE) model for meta-analysis of heterogeneous studies. It is shown that the known issues of underestimation of the statistical error and spuriously overconfident estimates with the RE model can be resolved by the use of an estimator under the fixed effect model assumption with a quasi-likelihood based variance structure - the IVhet model. Extensive simulations confirm that this estimator retains a correct coverage probability and a lower observed variance than the RE model estimator, regardless of heterogeneity. When the proposed IVhet method is applied to the controversial meta-analysis of intravenous magnesium for the prevention of mortality after myocardial infarction, the pooled OR is 1.01 (95% CI 0.71-1.46) which not only favors the larger studies but also indicates more uncertainty around the point estimate. In comparison, under the RE model the pooled OR is 0.71 (95% CI 0.57-0.89) which, given the simulation results, reflects underestimation of the statistical error. Given the compelling evidence generated, we recommend that the IVhet model replace both the FE and RE models. To facilitate this, it has been implemented into free meta-analysis software called MetaXL which can be downloaded from www.epigear.com.

People have some ability to adapt to their local climate type, but both cold and hot temperatures are still associated with increased risk of mortality. Public health strategies to alleviate the impact of ambient temperatures are important, in particular in the context of climate change.