Noncompliance to iodine supplementation recommendation is a risk factor for iodine insufficiency in Portuguese pregnant women: results from the IoMum cohort

Autores da FMUP

• Alexandre Rui Rodrigues Almeida

  Autor

• Claudia Camila Rodrigues Pereira Dias

  Autor

• Luís Filipe Ribeiro De Azevedo

  Autor

• Carla Maria De Almeida Ramalho

  Autor

• Elisa Oliveira Braga Keating

  Autor

Participantes de fora da FMUP

• Coelho, CM
• Guimaraes, J
• Bracchi,
• Moreira, NX
• Pinheiro, C
• Ferreira, P
• Pestana, D
• Mota, IB
• Cortez, A
• Prucha, C
• Martins, C
• Pinto, E
• Delerue-Matos, C
• Moreira-Rosário, A
• Fernandes, VC
• Calhau, C
• Brantsæter, AL
• Leite, JC

Unidades de investigação

• Biomedicina

• Cirurgia e Fisiologia

• Ginecologia-Obstetrícia e Pediatria

• Laboratório Associado RISE- Rede de Investigação em Saúde

  

  Investigador

  Fernando Carlos De Landér Schmitt

• Medicina da Comunidade, Informação e Decisão em Saúde

• Recursos Comuns

  

  Investigador

  Guilhermina Maria Da Silva Rêgo

• RISE-Health

  

  Investigador

  Fernando Carlos De Landér Schmitt

Abstract

Purpose After a recommendation for iodine supplementation in pregnancy has been issued in 2013 in Portugal, there were no studies covering iodine status in pregnancy in the country. The aim of this study was to assess iodine status in pregnant women in Porto region and its association with iodine supplementation. Methods A cross-sectional study was conducted at Centro Hospitalar Universitario Sao Joao, Porto, from April 2018 to April 2019. Pregnant women attending the 1st trimester ultrasound scan were invited to participate. Exclusion criteria were levothyroxine use, gestational age < 10 and >= 14 weeks, non-evolutive pregnancy at recruitment and non-signing of informed consent. Urinary iodine concentration (UIC) was measured in random spot urine by inductively coupled plasma-mass spectrometry. Results Median UIC was 104 mu g/L (IQR 62-189) in the overall population (n = 481) of which 19% had UIC < 50 mu g/L. Forty three percent (n = 206) were not taking an iodine-containing supplement (ICS) and median UIC values were 146 mu g/L (IQR 81-260) and 74 mu g/L (IQR 42-113) in ICS users and non-users, respectively (p < 0.001). Not using an ICS was an independent risk factor for iodine insufficiency [adjusted OR (95% CI) = 6.00 (2.74, 13.16); p < 0.001]. Iodised salt use was associated with increased median iodine-to-creatinine ratio (p < 0.014). Conclusions A low compliance to iodine supplementation recommendation in pregnancy accounted for a mild-to-moderately iodine deficiency. Our results evidence the need to support iodine supplementation among pregnant women in countries with low household coverage of iodised salt. Trial registration number NCT04010708, registered on the 8th July 2019.

Keywords

• Pregnancy; Urinary iodine; Iodine supplement use; Iodine status; Iodine deficiency