Urinary Creatinine Concentrations and Its Explanatory Variables in General Chinese Population: Implications for Creatinine Limits and Creatinine Adjustment.

Objective: The study aimed to analyze the applicability of the World Health Organization's exclusionary guidelines for Urinary creatinine (Ucr) in the general Chinese population, and to identify Ucr related factors. Methods: We conduct a cross-sectional study using baseline data from 21,167 participants in the China National Human Biomonitoring Program. Mixed linear models and restricted cubic splines (RCS) were used to analyze the associations between explanatory variables and Ucr concentration. Results: The geometric mean and median concentrations of Ucr in the general Chinese population were 0.90 g/L and 1.01 g/L, respectively. And 9.36% samples were outside 0.3-3.0 g/L, including 7.83% below the lower limit and 1.53% above the upper limit. Middle age, male, obesity, smoking, higher frequency of red meat consumption and chronic kidney disease were associated significantly with higher concentrations of Ucr. Results of the RCS showed Ucr was positively and linearly associated with body mass index, inversely and linearly associated with systolic blood pressure, diastolic blood pressure, triglycerides level, and glomerular filtration rate, and were non-linearly associated with triiodothyronine. Conclusion: The age- and gender-specific cut-off values of Ucr that determine the validity of urine samples in the general Chinese population were recommended. To avoid introducing bias into epidemiologic associations, the potential predictors of Ucr observed in the current study should be considered when using Ucr to adjust for variations in urine dilution.

Associations of Sarcopenia, Handgrip Strength and Calf Circumference with Cognitive Impairment among Chinese Older Adults.

OBJECTIVE: To evaluate the associations of sarcopenia, handgrip strength and calf circumference with cognitive impairment among Chinese older adults. METHODS: Totally 2,525 older adults were recruited from the Healthy Aging and Biomarkers Cohort Study. Cognitive impairment was assessed by the Chinese Mini-Mental State Examination. Handgrip strength was calculated from the means of the right and left hand values. Calf circumference was measured at the site of maximum circumference of the non-dominant leg. The formula developed by Ishii was used to define sarcopenia. Multiple logistic regression was performed to evaluate the associations of sarcopenia, handgrip strength, and calf circumference with cognitive impairment. RESULTS: The prevalence of cognitive impairment was 34.36%. The adjusted odds ratio ( OR) for cognitive impairment in individuals with sarcopenia was 2.55 [95% confidence interval (95% CI): 1.86-3.50]. Compared with individuals in the first quartile (Q 1) of calf circumference, the adjusted ORs in the second, third, and fourth quartiles (Q 2, Q 3, and Q 4) were 0.75 (95% CI: 0.58-0.96), 0.59 (95% CI: 0.44-0.79), and 0.62 (95% CI: 0.45-0.8), respectively. Compared with individuals in Q 1 of handgrip strength, the adjusted ORs for Q 2, Q 3, and Q 4 were 0.49 (95% CI: 0.38-0.62), 0.31 (95% CI: 0.23-0.41), and 0.30 (95% CI: 0.21-0.44), respectively. CONCLUSION: Sarcopenia, identified by low handgrip strength and low calf circumference, was positively associated with cognitive impairment.