Table 7.
Summary of published studies on the associations of obesity with hypothyroidism and thyroid autoimmunity in adults*.
| Study [Ref.] | Country | Design | Participants (Ages, years; Female, %) | TSH reference value | Adjustment or matching factors | Main findings |
|---|---|---|---|---|---|---|
| Knudsen et al., 2005 | Denmark | Cross-sectional | 4,082 participants (18–65 years; NA) | 0.4–3.6 mIU/L | Age, sex, region of inhabitancy, and smoking. | A significant association between obesity and increasing serum TSH level (>3.6 mIU/L). |
| Asvold et al., 2009 | Norway | Cross-sectional | 27,097 participants (>40 years; 67.7%) | 0.5–3.5 mIU/L | Age, and smoking. | Significant associations between obesity and SCH both in men (OR = 1.83, 95%CI 1.43–2.35) and women (OR = 1.54, 95%CI 1.34–1.76); A significant association between obesity and overt hypothyroidism in women (OR = 1.66, 95%CI 1.14–2.42). |
| Gopinath et al., 2010 | Australia | Cohort | 1,768 participants (≥55 years with as mean age of 67.6 years; 54.4%) | 0.1–4.0 mIU/L | Age, and sex. | Significant associations of obesity with hypothyroidism (OR = 2.52, 95%CI 1.29–4.89) and overt hypothyroidism (OR = 4.05, 95%CI 1.74–9.41), but not for SCH (OR = 1.06, 95%CI 0.33–3.37) |
| Marzullo et al., 2010 | Italy | Case-control | 165 obese subjects and 118 controls (< 50 years with a mean age of 35.8 years; 59.5%) | 0.4–4.0 mIU/L (0.4–4.38 mIU/L for obese patients) | Age and sex. | Significant associations of obesity with hypothyroidism (OR = 3.43, 95%CI 1.35–8.74), but not for SCH (OR = 2.43, 95%CI 0.92–6.41) and overt hypothyroidism (OR = 10.75, 95%CI 0.62–186.5); A significant association between obesity and thyroid autoimmunity (OR = 1.86, 95%CI 1.08–3.21). |
| Amouzegar et al., 2017 | Iran | Cohort | 4,204 individuals (≥20 years with as mean age of 40.4 years; 54.4%) | 0.34–5.06 mIU/L | Age, sex, smoking, waist circumference, and TPOAb. | Significant associations of obesity with overt hypothyroidism (RR = 2.92, 95%CI 1.64–5.20) and SCH (RR = 1.54, 95%CI 1.14–2.07). |
| Valdés et al., 2017 | Spain | Cross-sectional | 3,928 participants (Aged 18–93 years with a mean of 50.0 years; 54.4%) | 0.6–5.5 mIU/L | Age, sex, smoking status, and urinary iodine concentrations | Significant association between obesity and SCH (OR = 1.80, 95%CI 1.10–2.92). |
*
Studies recruiting children, adolescents, or pregnant women were not reviewed in this table. NA, not available; RR, risk ratio; 95%CI, 95% confidence interval.