Cartilage turnover assessed with a newly developed assay measuring collagen type II degradation products: influence of age, sex, menopause, hormone replacement therapy, and body mass index

Abstract

Background: Cartilage normally has a slow turnover but in arthritis increased metabolism results in degradation of the tissue.

Objective: To assess cartilage turnover in a sample of the general population by an assay measuring cartilage derived urinary collagen type II (CTX-II) C-telopeptide degradation products.

Methods: CTX-II concentrations were measured in urine samples from 615 healthy men and women aged 20-87 years, and the influence of age, sex, menopause, hormone replacement therapy (HRT), and body mass index (BMI) was assessed.

Results: CTX-II concentrations showed age dependent variations, with notable differences between men and women. Mean (SD) CTX-II concentration in postmenopausal women (220 (118) ng/mmol, n=25) was significantly higher than in an age matched group of premenopausal women (112 (79) ng/mmol, n=26, p<0.001). CTX-II concentration in women using HRT (118 (57) ng/mmol, n=50) was significantly lower than in an age and BMI matched group of women not receiving HRT (215 (99) ng/mmol, n=50, p<0.001). In subjects with a BMI >or=25 kg/m(2), CTX-II concentrations were significantly higher than in those with a BMI <25 kg/m(2) (185 (114) v 148 (91) ng/mmol, p<0.001).

Conclusions: Cartilage turnover, as assessed by measuring urinary degradation products of CTX-II varies considerably with age, and significant differences between CTX-II levels in men and women as well as in pre- and postmenopausal women are found. Further studies are required to validate the marker for assessing cartilage degradation in arthritis.

Figures

Figure 1

Age dependent variations in (A) creatinine corrected urinary CTX-II; (B) creatinine corrected urinary CTX-I; and (C) serum osteocalcin concentrations in women (open circle) and men (filled circle) aged 20–87. Results shown are means (SEM). Table 1 shows the number of men and women at each age.

Figure 2

Influence of age and menopausal status on creatinine corrected urinary CTX-II concentrations in women. (A) A scatterplot presenting individual values of premenopausal (filled circle) and postmenopausal (open circle) women. (B) Influence of menopausal status itself in women aged 49–53. Mean (SEM), ***p

Figure 3

(A) Influence of HRT on creatinine corrected urinary CTX-II concentrations independently of age and BMI. (B) Creatinine corrected urinary CTX-II concentrations in women having received HRT for 0–4 years and 4–10 years, respectively. Results shown are mean with SEM. *p

Figure 4

Influence of BMI on creatinine corrected urinary CTX-II concentrations in subjects older than 35 years of age. Results are adjusted for age and shown as mean with SEM. *p