Table 1. Characteristics of epidemiological studies investigating the association of maternal iron status and long-term offspring blood pressure levels.

Study identification	Design	Study size (number)	Exposure assessment	Main outcome	Main finding
Belfort et al (2008)50	Prospective cohort	1,167	Semiquantitative FFQ in the first second trimesters, Hb and MCV extracted from electronic laboratory database	Offspring BP at 3 y	Maternal iron intake positively associated with offspring BP
Brion et al (2008)51	Prospective cohort	1,255 (Hb) 7,484 (supplement) 7,130 (diet)	FFQ at 32 wk, questionnaires at 18 and 32 wk for supplements, Hb extracted from medical records	Offspring BP at 7 y	Maternal anemia associated with lower offspring BP in women not taking supplements
Law et al (1991)54	Historical cohort	405	Lowest Hb during pregnancy extracted from medical records	Offspring BP at 4 y	Maternal anemia associated with higher offspring BP
Godfrey et al (1994)55	Prospective cohort	77	Lowest Hb out of a maximum of 6 measurements throughout pregnancy	Offspring BP at 10–12 y	Negative association
Whincup et al (1994)56	Historical cohort	662	Lowest Hb in pregnancy and change in MCV extracted from medical records	Offspring BP at 9–11 y	No association
Bergel et al (2000)53	Prospective RCT follow-up	518	Lowest Hb during pregnancy recorded in the trial	Offspring BP at 5–9 y	Positive association
Alwan et al (2014)52	Prospective cohort	2,958	Early pregnancy Hb	Offspring BP, arterial stiffness and endothelial function at age 10	No association
Alwan et al (2012)57	Prospective cohort, Mendelian randomization	348	Maternal genotype at single nucleotide polymorphisms in the HFE gene as instrumental variables	Offspring BP, waist circumference and body mass index in adulthood	No association

Abbreviations: BP, blood pressure; FFQ, food frequency questionnaire; HFE, hemochromatosis; MCV, mean corpuscular volume; RCT, randomized controlled trial.