Iodine nutritional status of women in their first trimester of pregnancy in Catalonia

Design: cross-sectional descriptive study conducted 2008–2009 in primary care centers in Barcelona, Spain. Participants: pregnant women >17 years in the first trimester (<13 weeks) who consented; Exclusions: thyroid disease, inability to contact, cognitive/sensory or language problems, or refusal. Data: urinary iodine concentration (first-morning urine) and dietary habits via standardized questionnaire. 985 recruited; UIC available in 970; 945 completed questionnaire. Mean age 30.6 years; 83.0% Spanish; 73.7% from urban areas.

Milk consumption: 1-2 glasses/day (200 mL per glass) or >2 glasses/day; iodized salt: regular use; daily iodine supplements (potassium iodide or iodine-containing vitamins); Duration: during the first trimester of pregnancy (2008–2009).

Median UIC: 172 μg/L; 43.1% had UIC < 150 μg/L. Milk consumption protected against UIC < 150 μg/L: 1-2 glasses/day (OR 0.636, 95% CI 0.45–0.90); >2 glasses/day (OR 0.593, 95% CI 0.37–0.95). Iodized salt (OR 0.678, 95% CI 0.51–0.90); iodine supplementation (OR 0.410, 95% CI 0.31–0.54). Simultaneous milk (≥1 glass/day) and iodized salt (OR 0.427, 95% CI 0.27–0.66). This protection is similar to that of iodine supplementation (OR 0.411, 95% CI 0.31–0.54). Conclusion: Median UIC indicates adequate iodine status by WHO/ICCIDD criteria; consuming iodized salt with milk substantially reduces risk of UIC <150 μg/L, similar to iodine supplementation. Public health implications: promote iodized salt and milk intake; monitor iodine content in milk; supplementation remains an option if diet is insufficient.