The association between serum calcium levels and Chvostek sign A population-based study

Background: The Chvostek sign-a contraction of ipsilateral facial muscles subsequent to percussion over the facial nerve-is considered a clinical indicator of hypocalcemia. I sought to evaluate the association between Chvostek sign and serum calcium levels. Methods: I performed a cross-sectional analysis of data gathered from a nationwide probability sample of 3,434 individuals, aged 25-74 years, in the First National Health and Nutrition Examination Survey, conducted from 1971 to 1975. Results: Increasing serum calcium levels were associated with an increased odds for a positive Chvostek sign. When compared to calcium levels in the lowest quartile (5.47-9.4 mg/dL), individuals with serum calcium levels of 9.4-9.6 mg/dL, 9.6-9.9 mg/dL, and 9.9-11.9 mg/dL had a 195% (95% confidence interval [CI] 23.3%-604%), 124% (95% CI -0.8% to 407%), and 159% (95% CI 33.8%-401%) increased odds-as opposed to the expected decreased odds-for a positive Chvostek sign. When adjusting for age, sex, and race, these increased odds were 220% (95% CI 32%-679%), 125% (95% 0.00%-409%), and 172% (35%-448%), respectively. For every 1 g/dL increase in serum calcium level, the odds for a positive Chvostek sign increased by 4% (95% CI 0.00%-8%). Conclusions: A positive Chvostek sign is informative of normal to increased serum calcium levels rather than hypocalcemia.