Sulphate and osteoarthritis: decrease of serum sulphate levels by an additional 3-h fast and a 3-h glucose tolerance test after an overnight fast.

Abstract

Low sulphate levels in blood may contribute to osteoarthritis by decreasing cartilage chondroitin sulphation. To measure serum levels of sulphate during 3 h of fasting or glucose ingestion after overnight fasts to determine how much sulphate lowering may occur during this period. Sera from 14 patients with osteoarthritis who fasted overnight were obtained every 15-30 min during 3 h of continued fasting and during 3 h after ingestion of 75 g of glucose. Sulphate was assayed by high-performance liquid chromatography with a Metrohm-Peak 761 Compact IC and simultaneously assayed for glucose by high-performance liquid chromatography with a Metrohm-Peak 817 Bioscan. Continuation of overnight fasting for 3 h resulted in a near-linear 3-h decrease in levels for all 14 patients ranging from 3% to 20% with a mean drop of 9.3%, whereas the 3-h decrease after glucose ingestion ranged from 10% to 33% with a mean drop of 18.9%. A 3-h continuation of fasting caused a marked reduction in serum sulphate levels, whereas ingestion of 75 g of glucose in the absence of protein resulted in doubling the reduction. This suggests that fasting and ingestion of protein-free calories may produce periods of chondroitin undersulphation that could affect osteoarthritis.