Subclinical hypothyroidism is associated with increased risk for cancer mortality in adult Taiwanese-a 10 years population-based cohort

• Published in: PloS one Vol. 10; no. 4; p. e0122955
• Main Authors: Tseng, Fen-Yu, Lin, Wen-Yuan, Li, Chia-Ing, Li, Tsai-Chung, Lin, Cheng-Chieh, Huang, Kuo-Chin
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-04-2015; Public Library of Science (PLoS)
• Subjects: Adult; Adults; Alcohol use; Alcoholic beverages; Asymptomatic Diseases - mortality; Body mass; Body mass index; Body size; Bone cancer; Breast cancer; Cancer; Cancer therapies; Chewing; Clinical medicine; Cohort Studies; Confidence intervals; Diabetes; Diabetes mellitus; Drinking behavior; Dyslipidemia; Endocrinology; Fatalities; Female; Females; Hazards; Health risks; Hospitals; Humans; Hypertension; Hypothyroidism; Hypothyroidism - complications; Hypothyroidism - mortality; Internal medicine; Kaplan-Meier Estimate; Male; Mastication; Medical prognosis; Medical research; Medical screening; Medicine; Metabolic disorders; Metastasis; Middle Aged; Mortality; Neoplasms - etiology; Neoplasms - mortality; Physical activity; Proportional Hazards Models; Regression analysis; Risk assessment; Risk Factors; Science; Skin; Smoking; Statistical analysis; Studies; Taiwan - epidemiology; Thyroid; Thyroid diseases; Thyroid gland; Thyroid-stimulating hormone; Thyroxine; Triglycerides; Womens health; Taiwan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0122955

The association between subclinical hypothyroidism (SCH) and cancer mortality is seldom discussed.
A total of 115,746 participants without thyroid disease history, aged 20 and above, were recruited from four nationwide health screening centers in Taiwan from 1998 to 1999. SCH was defined as a serum thyroid-stimulating hormone (TSH) level of 5.0-19.96 mIU/L with normal total thyroxine concentrations. Euthyroidism was defined as a serum TSH level of 0.47-4.9 mIU/L. Cox proportional hazards regression analyses were used to estimate the relative risks (RRs) of death from cancer for adults with SCH during a 10-year follow-up period.
Among 115,746 adults, 1,841 had SCH (1.6%) and 113,905 (98.4%) had euthyroidism. There were 1,532 cancer deaths during the 1,034,082 person-years follow-up period. Adjusted for age, gender, body mass index, diabetes, hypertension, dyslipidemia, smoking, alcohol drinking, betel nut chewing, physical activity, income, and education level, the RRs (95% confidence interval) of cancer deaths among subjects with SCH versus euthyroid subjects were 1.51 (1.06 to 2.15). Cancer site analysis revealed a significant increased risk of bone, skin and breast cancer among SCH subjects (RR 2.79, (1.01, 7.70)). The risks of total cancer deaths were more prominent in the aged (RR 1.71, (1.02 to 2.87)), in females (RR 1.69 (1.08 to 2.65)), and in heavy smokers (RR 2.24, (1.19 to 4.21)).
Subjects with SCH had a significantly increased risk for cancer mortality among adult Taiwanese. This is the first report to demonstrate the association between SCH and cancer mortality.