Association of niacin intake with constipation in adult: result from the National Health and Nutrition Examination.

BACKGROUND: Although dietary intake is believed to be associated with constipation, there is currently a lack of research exploring the relationship between niacin intake and constipation. Therefore, the aim of this study is to investigate the association between niacin intake in adults and constipation using data from the National Health and Nutrition Examination Survey (NHANES). METHODS: This study included 5170 participants (aged ≥ 20 years) from the NHANES survey conducted between 2009 and 2010. Participants who reported experiencing constipation "always", "most of the time", or "sometimes" in the past 12 months were defined as constipation cases. The daily niacin intake was obtained from dietary recall and dietary supplement recalls of the patients. Weighted multivariate logistic regression analysis, restricted cubic spline regression, subgroup analysis, and interaction analysis were used to assess the correlation between niacin intake and constipation. RESULTS: After adjustment for covariates, the multivariate logistic regression model showed that low niacin intake was associated with a higher risk of constipation (Model 1: OR: 0.917, 95% CI 0.854-0.985, P = 0.023; Model 2: OR: 0.871, 95% CI 0.794-0.955, P = 0.01). After dividing niacin intake into four groups, a daily intake of 0-18 mg niacin was associated with a higher risk of constipation (Model 1: OR: 1.059, 95% CI 1.012-1.106, P = 0.019; Model 2: OR: 1.073, 95% CI 1.025-1.123, P = 0.013). The restricted cubic spline regression analysis also showed a non-linear relationship between niacin intake and the risk of constipation. CONCLUSION: The findings of this study suggested that daily intake of 0-18 mg of niacin was associated with a higher risk of constipation compared to a daily intake of 18-27 mg of niacin.

[ELISA kit for detection of biliary vesicular protein and its preliminary clinical application].

OBJECTIVE: To establish a rapid and precise detective method of 33.5 kd vesicular protein and to screen an effective treatment of cholelithiasis. METHODS: Specific antibody of the biliary vesicular protein was obtained by immunizing rabbits and enzyme-linked immunosorbent assay (ELISA) kit was developed. The concentrations of 33.5 kd vesicular protein in serum and bile of gallstone patients and control were examined respectively. The effects of Cholagogue Dry Syrup and Eulektrol Capsule on decreasing 33.5 kd vesicular protein were also studied by ELISA kit. RESULTS: One-step ELISA equation was Y=0.035 X (r=0.99). The vesicular protein concentrations in serum and bile of cholesterol gallstone group [(179.8+/-97.9) mg/L and (213.4+/-70.1) mg/L respectively] were significantly (P<0.05) higher than in the pigment stone group and control. Data showed that, with 2-week administration, Cholagogue Dry Syrup significantly decreased both biliary and serum 33.5 kd vesicular protein of cholesterol gallstone patients, while Eulekrol Capsule and control groups didn't have the same results. CONCLUSION: The concentrations of 33.5 kd protein are different in cholesterol gallstone patients and healthy groups which might be related to cholesterol nucleation process. Cholagogue Dry Syrup is of cholagogic and litholytic effect by decreasing biliary lithogenesis.