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 Between High-Sensitivity C-Reactive Protein and All-Cause Mortality Among Oldest-Old in Chinese Longevity Areas: A Community-Based Cohort Study.

BACKGROUND: The association between high-sensitivity C-reactive protein (hsCRP) levels and all-cause mortality for the oldest-old (aged 80 years or older) remains unclear. We aimed to investigate the associations between hsCRP concentrations and the risks of all-cause mortality, and further identify the potential modifying factors affecting these associations among the oldest-old. METHODS: This prospective, community-based cohort study included 2,206 participants aged 80 years or older (median age 93.0 years) from the Healthy Aging and Biomarkers Cohort Study. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidential intervals (95% CIs) for all-cause mortality according to hsCRP quartiles and recommendation for relative risk categories of hsCRP levels (< 1.0, 1.0-3.0, and > 3.0 mg/L), with adjustment for sociodemographic information, lifestyle, physical examination, medical history, and other potential confounders. RESULTS: During a median follow-up period of 3.1 years (IQR: 1.6-3.9 years), 1,106 deaths were verified. After full adjustment for potential confounders, a higher hsCRP concentration was positively associated with an increased risk of all-cause mortality (P for trend < 0.001). Compared with the lowest quartile, the fully adjusted HRs of the second, third, and fourth quartiles were 1.17 (95% CI: 0.94, 1.46), 1.28 (95% CI: 1.01, 1.61), and 1.49 (95% CI: 1.20, 1.87), respectively. The association of hsCRP with all-cause mortality was modified by smoking status (P for interaction = 0.011), an increased risk of hsCRP with all-cause mortality showed among non-current smokers (HR: 1.17; 95% CI: 1.07, 1.28), but no significance was observed in current smokers (HR: 0.83; 95% CI: 0.66, 1.18). CONCLUSIONS: Our study indicated that elevated hsCRP concentrations were associated with a higher risk of all-cause mortality among Chinese oldest-old. Future studies investigating additional factors of disease and aging processes are needed to obtain a better understanding of the mechanisms.

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.