Prevalence of thyroid nodules and influencing factors among employees of a company in Qingdao

Abstract

To investigate the prevalence of thyroid nodules and influencing factors among employees of a company in Qingdao. Through questionnaires, physical examination, thyroid ultrasonography and urinary iodine test, personal health information and examinations of thyroid nodules of 9612 serving and retired employees in a company in 2010 who had lived in Qingdao for more than 5 years were collected to investigate the prevalence of thyroid nodules and its influencing factors. The prevalence of thyroid nodules was 36.56% (3514/9612). The prevalence rates of single nodules and multiple nodules were 18.39% (1768/9612) and 18.16% (1746/9612) respectively. With increasing urinary iodine level, the prevalence of multiple thyroid nodules decreased from 25.51% (366/14350)(urinary iodine < or = 100 microg/L) to 12.99% (214/1648) (urinary iodine > 300 microg/L) showing a clear downward trend (chi2 = 67.11, P < 0.01). The prevalence rates of thyroid nodules among males and females were 31.28% (2283/7299) and 53.22% (1231/2313) (P < 0.01) respectively. With increasing age, the prevalence of thyroid nodules gradually increased from 7.95% (67/843) (19 - 29 years old) to 58.81% (267/454) ( >70 years old) among males and increased from 23.74% (33/139) (19 - 29 years old) to 80.38% (127/158) ( >70 years old) among females. The prevalence of thyroid nodules among males and females showed an increasing trend with age (male: chi2 = 434.12, P < 0.01; female: chi2 = 40.74, P < 0.01). The results of logistic regression showed that compared with males, females were more susceptible to thyroid nodules (OR = 2.809, 95% CI: 2.444 - 3.228). Smoking (OR = 1.394, 95% CI: 1.249 - 1.556), hypertension (OR = 1.155, 95% CI: 1.040 - 1.282), diabetes ( OR = 1.228, 95% CI: 1.039 - 1.452) and overweight (OR = 1.199, 95% CI: 1.078 - 1.333) might be risk factors for thyroid nodules after adjusting for age and gender. The prevalence of thyroid nodules was high among the employees. In order to reduce the thyroid nodules, smoking cessation and weight control should be promoted. Blood pressure and glucose level should be actively controlled for patients with hypertension and (or) diabetes.