Changes of serum CTX-1 and P1NP in patients with skeletal fluorosis in tea-drinking-borne endemic fluorosis area in Qinghai Province / 中华地方病学杂志

ABSTRACT

Objective:To observe the changes of serum C-terminal peptide of type Ⅰ collagen (CTX-1) and N-terminal lengthening peptide of type Ⅰ collagen (P1NP) in adult patients with skeletal fluorosis in the tea-drinking-borne endemic fluorosis area in Qinghai Province, and to find sensitive indicators for diagnosis of skeletal fluorosis.Methods:From April to August 2019, a case-control study was carried out in tea-drinking-borne endemic fluorosis area in Zhiduo County, Yushu Tibetan Autonomous Prefecture, and Gangcha County, Haibei Tibetan Autonomous Prefecture of Qinghai Province. According to the Diagnostic Standard for Endemic Skeletal Fluorosis (WS/T 192-2008), the clinical diagnosis and X-ray examination of skeletal fluorosis were carried out for permanent residents ≥25 years old and living for more than 10 years in the area, combined with face-to-face inquiry and investigation of past disease history, lifestyle and clinical manifestations. The patients with skeletal fluorosis and healthy people were selected as skeletal fluorosis group and control group, respectively. Randomized urine samples and fasting venous blood from the two groups were collected. The content of fluoride in urine was determined by ion selective electrode method, and the contents of CTX-1 and P1NP in serum were determined by enzyme-linked immunosorbent assay (ELISA).Results:A total of 127 people in the disease area were investigated, including 63 cases in skeletal fluorosis group and 64 cases in control group. There was no statistically significant difference in age and sex ratio between the two groups ( t = 0.42, χ 2 = 0.07, P > 0.05). The X-ray examination results showed that the patients with skeletal fluorosis were mainly mild, accounting for 71.43% (45/63); X-ray changes were mainly ossification of interosseous membrane and tendon. The urinary fluoride in control group and skeletal fluorosis group was 1.62 (1.12, 1.95) and 3.22 (2.38, 4.89) mg/L, respectively, with statistically significant difference between the two groups ( Z = 7.07, P < 0.001). The difference of serum CTX-1 and P1NP contents between the two groups was statistically significant ( Z = 2.00, 4.89, P < 0.05). Conclusions:The levels of serum CTX-1 and P1NP in patients with skeletal fluorosis are higher than those in healthy people. Serum CTX-1 and P1NP may be used as sensitive indicators for diagnosis of skeletal fluorosis.