Changes in the composition of hospitalization of thyroid disease in Lianyungang City of Jiangsu Province from 2002 to 2010

Objective To analyze the changes in the composition of hospitalization of thyroid disease in Lianyungang City from 2002 to 2010, to learn the impact of iodine intake on thyroid disease in Lianyungang City after implementing universal salt iodization (USI), and to get epidemiologic evidence for prevention and control of iodine deficiency disorders scientifically. Methods Medical reports of the patients with thyroid disease were collected from hospitals at county level and above institutions in Lianyungang City from 2002 to 2010. Monitoring results of household iodized salt were also collected from five counties (districts) in Lianyungang City. The changes in the composition of hospitalization of thyroid disease were analyzed, and the relationship between thyroid disease and iodized salt was studied. Results ① A total of 3 559 patients with thyroid disease were enrolled in the study, the ratio between male and female was 1∶3.36. Mean age was (46.81 ± 14.94) years old and the peak age was from 40 to 60 years old. ② Among the hospitalized patients with thyroid disease, the proportion of goiter patients, hyperthyroidism patients, thyroiditis patients, hypothyroidism and other thyroid disorders was 41.64% (1 482/3 559), 40.07% (1 426/3 559), 6.83% (243/3 559), 6.21% (221/3 559) and 5.25% (187/3 559), respectively. ③ In 2002-2010, the hospitalization rate of thyroid disease showed an upward trend (χ2 = 460.12, P < 0.01), and the hospitalization rates of hypothyroidism, goiter, hyperthyroidism, thyroiditis and other thyroid disorders were all increased year by year (χ2 = 50.54, 281.91, 85.15, 19.51 and 65.01, all P < 0.01). ④From 2002 to 2006, among the patients with thyroid disease, the proportion of hyperthyroidism was the highest, and the range of values was from 42.03% (124/295) to 53.02% (114/215). Followed by goiter, and the range of values was from 34.55% (142/411) to 39.25% (73/186). From 2007 to 2010, the proportion of goiter became the highest, and the range of values was from 42.11% (232/551) to 49.57% (291/587). Followed by hyperthyroidism, and the range of values was from 33.05% (194/587) to 40.47% (223/551). ⑤From 2002 to 2010, the coverage of iodized salt and the consumption rate of qualified iodized salt both increased year by year (χ2 = 183.75, 211.99, all P < 0.01). ⑥ There were positive correlations between the hospitalization rates of thyroid disease, hypothyroidism, goiter, other thyroid disorders and the coverage of iodized salt, and the consumption rate of qualified iodized salt (rs = 0.83, 0.93, 0.82, 0.87, 0.83, 0.93, 0.74 and 0.91, all P < 0.05). ⑦ There was a positive correlation between the hospitalization rate of hyperthyroidism and the consumption rate of qualified iodized salt (rs = 0.72, P < 0.05). Conclusions There are some changes in the composition of hospitalization of thyroid disease in Lianyungang city from 2002 to 2010. Iodine intake may affect the hospitalization rate of thyroid disease. Key words: Iodine; Thyroid disease; Hospitalization rate; Disease spectrum; Composition