The study aimed to assess the effect of publication bias on the results and conclusions of systematic reviews and meta-analyses. It analyzed 48 reviews in the Cochrane Database of Systematic Reviews that considered a binary endpoint and contained 10 or more individual studies. The trim and fill method was used to estimate the number of missing studies and their impact on the conclusions of the meta-analyses. The method both tests for the presence of publication bias and adjusts for it. The results showed that 26 (54%) of the reviews had missing studies, with 10 having a significant number of missing studies. Using a random effects model, the corresponding figures were 23 (48%) and eight. In four cases, statistical inferences regarding the effect of the intervention were changed after adjusting for publication bias. The study concluded that publication or related biases were common within the sample of meta-analyses assessed. However, these biases did not affect the conclusions in most cases. Researchers should check routinely whether conclusions of systematic reviews are robust to possible non-random selection mechanisms. The study also compared the prevalence of low back pain and associated disability in two postal surveys conducted 10 years apart in Britain. The first survey was conducted in 1987-8 and obtained information from 2667 men and women randomly selected from the lists of 136 general practitioners in eight geographically dispersed locations in Britain. The second survey was conducted in 1997 and obtained information from 2667 men and women randomly selected from the lists of 136 general practitioners in eight geographically dispersed locations in Britain. The results showed that the prevalence of low back pain and associated disability had increased significantly over the 10-year period. The study concluded that the increase in prevalence was likely due to a combination of factors, including changes in people's behavior when they have symptoms and an increase in the occurrence of diseases affecting the back.The study aimed to assess the effect of publication bias on the results and conclusions of systematic reviews and meta-analyses. It analyzed 48 reviews in the Cochrane Database of Systematic Reviews that considered a binary endpoint and contained 10 or more individual studies. The trim and fill method was used to estimate the number of missing studies and their impact on the conclusions of the meta-analyses. The method both tests for the presence of publication bias and adjusts for it. The results showed that 26 (54%) of the reviews had missing studies, with 10 having a significant number of missing studies. Using a random effects model, the corresponding figures were 23 (48%) and eight. In four cases, statistical inferences regarding the effect of the intervention were changed after adjusting for publication bias. The study concluded that publication or related biases were common within the sample of meta-analyses assessed. However, these biases did not affect the conclusions in most cases. Researchers should check routinely whether conclusions of systematic reviews are robust to possible non-random selection mechanisms. The study also compared the prevalence of low back pain and associated disability in two postal surveys conducted 10 years apart in Britain. The first survey was conducted in 1987-8 and obtained information from 2667 men and women randomly selected from the lists of 136 general practitioners in eight geographically dispersed locations in Britain. The second survey was conducted in 1997 and obtained information from 2667 men and women randomly selected from the lists of 136 general practitioners in eight geographically dispersed locations in Britain. The results showed that the prevalence of low back pain and associated disability had increased significantly over the 10-year period. The study concluded that the increase in prevalence was likely due to a combination of factors, including changes in people's behavior when they have symptoms and an increase in the occurrence of diseases affecting the back.