Some studies have found a significant relationship between birth weight (BW) and the risk of coronary heart disease (CHD) in adulthood, but results were inconsistent. The purpose of this study was to characterize the association between BW and the risk of CHD in adults. Among 144 papers detected by our search, 27 papers provided data on the relationship between BW and CHD, of which 23 papers considered BW as a continuous variable, and 14 articles considered BW as a categorical variable for this meta-analysis. Based on 23 papers, the mean weighted estimate for the association between BW and the combined outcome of non-fatal and fatal CHD was 0.83 [95% confidence interval (CI), 0.80-0.86] per kilogram of BW (P<0.0001). Low birth weight (LBW<2500 g) was associated with increased risk of CHD [odds ratio (OR), 1.19; 95% confidence interval (CI), 1.11-1.27] compared with subjects with BW⩾2500 g. LBW, as compared with normal BW (2500-4000 g), was associated with increased risk of CHD (OR, 1.16; 95% CI, 1.08-1.25). High birth weight (HBW⩾4000 g) was associated with decreased risk of CHD (OR, 0.89; 95% CI, 0.81-0.98) compared with subjects with BW<4000 g. In addition, there was an indication (not quite significant) that HBW was associated with a lower risk of CHD (OR, 0.89; 95% CI, 0.79-1.01), as compared with normal BW. No significant evidence of publication bias was present. These results suggest that LBW is significantly associated with increased risk of CHD and a 1 kg higher BW is associated with a 10-20% lower risk of CHD.

A number of randomized controlled trials (RCTs) examining the role of vitamin K on bone mineral density (BMD) have yielded inconsistent results. We performed a meta-analysis of these trials to assess the effect of vitamin K on BMD. We searched MEDLINE, EMBASE and CENTRAL for relevant studies of RCTs examining the role of vitamin K on BMD. Data on participants, interventions, and outcomes were extracted and the quality of all included trials assessed. Primary outcomes for analysis were absolute changes in BMD (mg/cm(2)) at the lumbar spine and femoral neck. Relative changes (percentage change) in BMD at the lumbar spine were also assessed. Vitamin K supplementation was shown to be efficacious in increasing BMD at the lumbar spine but not the femoral neck. The weighted mean difference (WMD) in BMD absolute change was 21.60 mg/cm(2) [95% confidence interval (CI) 3.63, 39.56] at the lumbar spine and 0.25 mg/cm(2) (95% CI -2.64, 3.14) at the femoral neck. The WMD in BMD relative change was 1.27% (95% CI 0.47, 2.06) at the lumbar spine and 0.17 (95% CI -0.21, 0.54) at the femoral neck. Subgroup analysis revealed that ethnic difference, gender, and vitamin K type were associated with variable effects on BMD at the lumbar spine. The modest overall treatment effects for vitamin K on BMD observed in this review may be biased and should be interpreted with caution. Further studies are required to address factors relating to the observed effects of vitamin K on BMD.

The results of our study indicate that increased BMI modestly associates with later ANM. The relationship between BMI and ANM needs further clarification in well-designed studies, especially studies well-controlled for smoking status.

The present study indicated that pre-pregnancy obesity increases the risks of delayed lactogenesis II and early termination of any breast-feeding in Chinese women.

This meta-analysis suggested that TNF-α gene promoter polymorphism at position -238 but not -308 might be a risk factor for NAFLD.