Transient hypoparathyroidism during acute alcohol intoxication.

BACKGROUND: Persons with chronic alcoholism frequently have hypocalcemia, hypomagnesemia, and osteoporosis. The short-term effects of alcohol ingestion on calcium and magnesium metabolism are poorly understood, however.
METHODS: We measured serum calcium, magnesium, and phosphate concentrations in 17 normal men and 7 normal women before and at intervals up to 16 hours after the ingestion of 1.2 to 1.5 g of alcohol per kilogram of body weight over a 3-hour period (doses sufficient to cause acute intoxication). Urinary excretion of calcium, magnesium, and phosphate and serum calciotropic hormone levels were measured in 16 of these subjects. As a control, the same measurements were made after the ingestion of fruit juice instead of alcohol.
RESULTS: The mean (+/- SE) peak blood alcohol level in the men was 37.5 +/- 1.6 mmol per liter, and in the women it was 38.0 +/- 3.2 mmol per liter. In the men the mean serum parathyroid hormone concentration decreased from 16.1 +/- 2.1 to 6.8 +/- 0.9 ng per liter at the end of the three-hour drinking period. The value at this time was 30 percent of that at the end of the three-hour session during which the men drank fruit juice (P = 0.004). The serum concentration of ionized calcium reached a nadir eight hours after the beginning of alcohol administration (decreasing from 1.18 +/- 0.01 to 1.15 +/- 0.01 mmol per liter; P less than 0.001 as compared with values during the fruit-juice study), and urinary excretion of calcium increased from 0.34 +/- 0.08 to 0.36 +/- 0.08 mmol per hour (P less than 0.01 as compared with values during the fruit-juice study). Serum parathyroid hormone levels exceeded base-line values during the last 4 hours of the 16-hour study period; this increase was accompanied by a decrease in the urinary excretion of calcium. Both serum levels of magnesium (in the first 6 hours) and urinary levels (in the first 12 hours) increased after the ingestion of alcohol. In the women, serum parathyroid hormone levels decreased from 29.2 +/- 2.8 to 17.3 +/- 2.6 ng per liter two hours after the administration of alcohol was begun (P less than 0.001) and increased above base-line values during the last four hours of the study period. The serum concentration of ionized calcium decreased from 1.20 +/- 0.01 to 1.16 +/- 0.01 mmol per liter, reaching a nadir 8 to 12 hours after alcohol administration was begun (P less than 0.001).
CONCLUSIONS: Short-term alcohol administration causes transitory hypoparathyroidism. This decline in the secretion of parathyroid hormone accounts at least in part for the transient hypocalcemia, hypercalciuria, and hypermagnesuria that follow alcohol ingestion.