Objective:To evaluate the changes in vitamins and trace elements in obese patients after laparoscopic sleeve gastrectomy (LSG).Methods:A systematic retrieval of the available literature was performed using Pubmed, Embase, Cochrane library, Web of Science, WanFang data and CNKI databases and studies were selected per predefined eligibility criteria. Statistical analysis was performed using Stata 13.0.Results:A total of 22 studies with 5320 individuals with obesity who underwent LSG were identified as eligible for inclusion. A significant increase was observed in serum 25(OH)D ( SMD = 0.59, 95% CI: 0.16 to 1.03, P = 0.007), phosphorus ( SMD = 0.28, 95% CI: 0.09 to 0.47, P = 0.004) and iron ( SMD = 0.46, 95% CI: 0.31 to 0.61, P < 0.01) after LSG. A significant decrease in serum zinc ( SMD = -0.41, 95% CI: -0.81 to -0.01, P = 0.044) was observed after LSG. But no significant changes in serum calcium ( SMD = 0.11, 95% CI: -0.14 to 0.36, P = 0.385), folate ( SMD = 0.27, 95% CI: -0.08 to 0.62, P = 0.133), vitamin B 12 ( SMD = 0.11, 95% CI: -0.25 to 0.47, P = 0.563) and magnesium ( SMD = 0.53, 95% CI: -0.08 to 1.14, P = 0.09) were observed. Conclusions:The changes of serum nutritional measurements in individuals with obesity who underwent LSG are uncertain. Therefore, it is recommended to monitor the nutritional laboratory values and add supplements when necessary to prevent postoperative malnutrition.

To explore the threshold effect of body mass index (BMI) on bone mineral density (BMD) in Chinese women living in the fluorosis area, we conducted a cross-sectional study and recruited 722 women in rural areas in Henan Province, China. After detection and analyses, we found that compared with the normal BMI group, the risk of osteoporosis in the overweight and obese groups were reduced by 32% and 69%, respectively. Threshold effect analysis showed that BMD was positively correlated with BMI when BMI was 16.8-31.2 kg/m 2; while when BMI was greater than 31.2 kg/m 2, the correlation reached saturation. The correlation observed between low-to-moderate fluoride exposure and BMD in rural women was not significant.

To explore the threshold effect of body mass index (BMI) on bone mineral density (BMD) in Chinese women living in the fluorosis area, we conducted a cross-sectional study and recruited 722 women in rural areas in Henan Province, China. After detection and analyses, we found that compared with the normal BMI group, the risk of osteoporosis in the overweight and obese groups were reduced by 32% and 69%, respectively. Threshold effect analysis showed that BMD was positively correlated with BMI when BMI was 16.8-31.2 kg/m 2; while when BMI was greater than 31.2 kg/m 2, the correlation reached saturation. The correlation observed between low-to-moderate fluoride exposure and BMD in rural women was not significant.