Seasonal changes of serum 25-hydroxyvitamin D and intact parathyroid hormone levels in a normal Japanese population

• Published in: Journal of bone and mineral metabolism Vol. 23; no. 2; pp. 147 - 151
• Main Authors: Ono, Yasunaga, Suzuki, Atsushi, Kotake, Motoko, Zhang, Xiaoli, Nishiwaki-Yasuda, Keiko, Ishiwata, Yoko, Imamura, Shigeo, Nagata, Mutsuko, Takamoto, Satoru, Itoh, Mitsuyasu
• Format: Journal Article
• Language: English
• Published: Tokyo Springer 01.03.2005; Springer Nature B.V
• Subjects: Adult; Aged; Biological and medical sciences; Diseases of the osteoarticular system; Female; Humans; Japan - epidemiology; Male; Medical sciences; Middle Aged; Older people; Parathyroid Hormone - blood; Reference Values; Regression Analysis; Seasons; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D Deficiency - epidemiology; Vitamin deficiency; Asia; Japan; Human; Prevalence; Body weight; Nutrition disorder; Hypovitaminosis D; Hypovitaminosis; Summer; Male; Concentration; Normal; Epidemiology; Japanese; Blood plasma; Winter; Parathyroid hormone; Seasonal variation; Radioimmunoassay; Intact PTH; Female; Serum; End; Woman; Age
• ISSN: 0914-8779; 1435-5604
• DOI: 10.1007/s00774-004-0553-8

We conducted an observational study in order to assess the prevalence of hypovitaminosis D and its seasonal changes, in the Tokai area (N35.3 E137.0), in 197 normal subjects in Japan. The mean serum 25-hydroxyvitamin D (25-OHD) level measured by direct radioimmunoassay (RIA) was lowest at the end of winter, and highest at the end of summer (15.1+/-7.1 ng/ml in March; 21.5+/-5.5 ng/ml in June; 31.6+/-5.6 ng/ml in September; 23.1+/-5.3 ng/ml in December; mean+/-SD). The prevalence of hypovitaminosis D (<20 ng/ml) was 86.7%, 33.4%, 1.0%, and 26.0% in March, June, September, and December, respectively. Mean plasma intact parathyroid hormone (iPTH) concentration was lowest at the end of summer and highest at the end of winter (28.2+/-9.3 pg/ml in March; 21.7+/-7.0 pg/ml in June; 19.8+/-6.9 pg/ml in September; and 25.7+/-9.2 pg/ml in December; mean+/-SD). Serum 25-OHD was inversely associated with iPTH (coefficient, -0.223; r=0.251; P<0.001). Serum 25-OHD levels were higher in men than in women. The serum 25-OHD level was positively associated with age, body weight, and body mass index, but not with body fat content. These results suggest a high prevalence of hypovitaminosis D associated with elevation of iPTH in Japan, in winter, even in a sunny area.