Low relative skeletal muscle mass indicative of sarcopenia is associated with elevations in serum uric acid levels: findings from NHANES III.

BACKGROUND: Sarcopenia may be related to increases in reactive oxygen species formation and inflammation, both of which are associated with elevations in serum uric acid. OBJECTIVE: To test the hypothesis that a reduced skeletal muscle mass index, indicative of sarcopenia, is related to elevations in uric acid. DESIGN: Cross-sectional analysis of nationally representative data. SETTING: Third National Health and Nutrition Examination Survey, 1988-1994. PATIENTS: 7544 men and women 40 years of age and older who had uric acid, skeletal muscle mass, and select covariate information. MEASUREMENTS: Skeletal muscle mass assessment was based on a previously published equation including height, BIA-resistance, gender, and age. Absolute skeletal muscle mass was calculated for all study population individuals and compared against the sex-specific mean for younger adults. Serum uric acid data were gathered from the NHANES laboratory file. RESULTS: A logistic regression analysis revealed that elevations in serum uric acid are significantly related to sarcopenia status. For every unit (mg/dL) increase in uric acid, the odds ratio of manifesting a skeletal muscle mass index at least one standard deviation below the reference mean was 1.12. Participants in the highest grouping (> 8 mg/dL) of serum uric acid concentration had 2.0 times the odds of manifesting sarcopenia compared to the lowest grouping (< 6 mg/dL) (p < 0.01) after adjusting for the additional covariates. LIMITATIONS: This study design was limited in its cross-sectional nature. Potential selection, measurement, and recall bias may have occurred, and methodology used to classify sarcopenia status based on skeletal muscle mass index is not validated. CONCLUSION: This observation provides support for the theory that elevations in uric acid may lead to sarcopenia, although the proposed mechanism needs further experimental support.

Assessing risk using different cholesterol-screening methods.

The purpose of this study was to compare total capillary, total venous, risk ratio, high-density lipoprotein and low-density lipoprotein measures of cholesterol to determine whether total capillary cholesterol is a valid measure to use in cholesterol screening. An announcement and a registration form were distributed with employee paychecks announcing a cholesterol-screening programme. Capillary and venous samples were collected from screening participants (n=285). Results indicated false negatives in total capillary cholesterol in 17.21-34.4% of cases compared with other methods of cholesterol measurement. Due to the high number of misclassifications, health educators should not use total capillary cholesterol as a predictor of risk for heart disease, nor as a measure for referral during cholesterol screenings.

High-cost analysis. A closer look at the case for work-site health promotion.

Studies linking medical costs to behavioral risk and risk-lowering often use means for comparisons, although claims data are highly skewed. The result overestimates and obscures the case for work-site health promotion. In this study, high-cost analysis is illustrated in a sample of university employees. Five risk factors were examined: cholesterol, blood pressure, cardiovascular fitness, body fat, and smoking status. Screened employees who released their claims (n = 367) were examined against a random sample of employees (n = 587). Linear regression was used to determine the risk of having high claims costs within four gender-specific age groups. A formula was then applied to determine that more than 43% of the cost of medical claims was associated with elevated risk. High-cost analysis accounts for the skewness in claims data and presents a clear case for work-site health promotion.