[An epidemiological survey of the prevalence of thyroid diseases in mild iodine deficiency city after salt iodization].

OBJECTIVE: To investigate the current status of iodine nutrition and the prevalence of thyroid diseases in Guiyang, a mild iodine deficiency city practiced salt iodization for 25 years. METHODS: A representative sample of 1509 adults aged 20 years old or above in Guiyang, selected by a multistage stratified sampling method, participated in the study. After an overnight fasting, serum thyroid hormones, serum thyroid autoantibodies, and urine iodine were measured. B-mode ultrasonography of the thyroid was performed in the population. Meanwhile, urine iodine of 80 children aged 8 - 10 years old in the same community were measured after an overnight fasting. RESULTS: The median of 8-10 years old children's urinary iodine was 228.7 µg/L. The prevalence of overt hypothyroidism, subclinical hypothyroidism, overt hyperthyroidism and subclinical hyperthyroidism was 1.79%, 14.12%, 1.52% and 1.06% respectively. The prevalence of subclinical hypothyroidism was significantly higher than overt hypothyroidism (P < 0.05) and was significantly higher in female than that in male (P < 0.05). The prevalence of positive thyroid peroxidase antibody, positive thyroglobulin antibody and autoimmune thyroiditis was 14.38%, 13.59% and 4.44% respectively, which were significantly higher in female than that in male (all P values < 0.05). The prevalence of diffuse goiter and nodular goiter was 0.86% and 0.20% respectively, with a significant difference (P < 0.05). CONCLUSION: After 25 years of salt iodization, the iodine nutrition in Guiyang is more than adequate with high prevalence of overt hypothyroidism, subclinical hypothyroidism and autoimmune thyroiditis.

[Survey of vitamin D status in 700 healthy adult males in Guiyang, China].

OBJECTIVE: To evaluate the vitamin D status of healthy adult males living in Guiyang. METHODS: A total of 700 healthy volunteers aged 20 - 79 years were selected randomly from a community in Guiyang by stratified sampling method. Questionnaires for living habits and fasting blood samples were collected in the morning from November 2009 to January 2010. The serum concentrations of 25-hydroxyvitamin D were measured by the DiaSorin radioimmunoassay kit. RESULTS: The mean levels of serum 25(OH)D was (21 ± 10) µg/L. And the percentages of vitamin D deficiency (25(OH)D < 20 µg/L), insufficiency (20 µg/L ≤ 25(OH)D < 30 µg/L) and sufficiency (25(OH)D ≥ 30.0 µg/L) were 315(50.2%), 202 (32.2%) and 110(17.6%)respectively. The concentrations of serum 25(OH)D in young, middle-aged and old adults were (18 ± 10) µg/L, (24 ± 10) µg/L and (22 ± 8)µg/L respectively. The serum level of 25(OH)D was lower in the smokers than that in the non-smokers (20 µg/L vs 22 µg/L, P = 0.003). The serum concentrations of 25(OH)D were (24 ± 10) µg/L, (23 ± 10) µg/L, (22 ± 9) µg/L and (18 ± 9) µg/L in education level (≤ 6, 7 - 9, 10 - 12 and ≥ 10 years in school) respectively. Significant inverse correlations existed between the concentrations of serum 25(OH)D and the education levels (r = -0.138, P = 0.000). CONCLUSION: The prevalence of hypovitaminosis D is common in healthy adult males in Guiyang, especially among the youth, smokers and higher educated groups.