Abstract
RATIONALE:
A potential adverse effect of high folate intake during pregnancy on children's asthma development remains controversial.
OBJECTIVES:
To prospectively investigate folate intake from both food and supplements during pregnancy and asthma at age seven years when the diagnosis is more reliable than at preschool age.
METHODS:
This study included eligible children born 2002-2006 from the Norwegian Mother and Child Cohort Study, a population-based pregnancy cohort, linked to the Norwegian Prescription Database. Current asthma at age seven was defined by asthma medications dispensed at least twice in the year (1,901 cases, n=39,846) or by maternal questionnaire report (1,624 cases, n=28,872). Maternal folate intake was assessed with a food frequency questionnaire validated against plasma folate. We used log-binomial and multinomial regression to calculate adjusted relative risks with 95% confidence intervals.
MEASUREMENTS AND MAIN RESULTS:
Risk of asthma was increased in the highest vs. lowest quintile of total folate intake with an adjusted relative risk of 1.23 (95% confidence interval 1.06 to 1.44) that was similar for maternally reported asthma. Mothers in the highest quintile had a relatively high intake of food folate (median 308, interquartile range 241-366 μg/day) and nearly all took at least 400 μg/day of supplemental folic acid (median 500, interquartile range 400-600).
CONCLUSIONS:
In this large prospective population based cohort with essentially complete follow-up, pregnant women taking supplemental folic-acid at or above the recommended dose, combined with a diet rich in folate, reach a total folate intake level that may slightly increase risk of asthma in children.
A potential adverse effect of high folate intake during pregnancy on children's asthma development remains controversial.
OBJECTIVES:
To prospectively investigate folate intake from both food and supplements during pregnancy and asthma at age seven years when the diagnosis is more reliable than at preschool age.
METHODS:
This study included eligible children born 2002-2006 from the Norwegian Mother and Child Cohort Study, a population-based pregnancy cohort, linked to the Norwegian Prescription Database. Current asthma at age seven was defined by asthma medications dispensed at least twice in the year (1,901 cases, n=39,846) or by maternal questionnaire report (1,624 cases, n=28,872). Maternal folate intake was assessed with a food frequency questionnaire validated against plasma folate. We used log-binomial and multinomial regression to calculate adjusted relative risks with 95% confidence intervals.
MEASUREMENTS AND MAIN RESULTS:
Risk of asthma was increased in the highest vs. lowest quintile of total folate intake with an adjusted relative risk of 1.23 (95% confidence interval 1.06 to 1.44) that was similar for maternally reported asthma. Mothers in the highest quintile had a relatively high intake of food folate (median 308, interquartile range 241-366 μg/day) and nearly all took at least 400 μg/day of supplemental folic acid (median 500, interquartile range 400-600).
CONCLUSIONS:
In this large prospective population based cohort with essentially complete follow-up, pregnant women taking supplemental folic-acid at or above the recommended dose, combined with a diet rich in folate, reach a total folate intake level that may slightly increase risk of asthma in children.
| Original language | English |
|---|---|
| Pages (from-to) | 155-156 |
| Number of pages | 26 |
| Journal | American Journal of Respiratory and Critical Care Medicine |
| Volume | 195 |
| Issue number | 2 |
| Early online date | 12 Aug 2016 |
| DOIs | |
| Publication status | Published - 15 Jan 2017 |
Keywords
- children's asthma development
- birth cohort
- epidemiology
- maternal diet