Early lung function deficits represent a significant risk factor for the evolution toward chronic obstructive pulmonary disease later in life. Prematurity and in utero tobacco smoke exposure are already known to predispose children to develop a non-reversible obstructive ventilatory defect in adulthood. The role of vitamin D status during pregnancy is less certain. In humans, low vitamin D concentrations during pregnancy are associated to an increased risk of asthma in children. In murine models, low vitamin D concentrations during pregnancy are associated to structural abnormalities of the airways in mouse pups. Investigators hypothesized that vitamin D play a role in early airways development, from the first trimester of pregnancy. To bring arguments to this hypothesis, the investigators will study the association of airway resistance in children aged 5 to 6 years old with the concentration of vitamin D during the first trimester of pregnancy in their mothers.
Children aged 5 to 6 years old will be included from the FEPED cohort. The FEPED cohort is a cohort of French pregnant women designed to study the association between vitamin D status during pregnancy and the risk of pre-eclampsia. Vitamin D concentration at first and third trimester of pregnancy as well as in cord blood is available for 1400 women. Investigators will include 200 children born from these women. Children will undergo lung function tests and prick-tests and parents will answer the ISAAC questionnaire that is a standardised questionnaire designed to evaluate asthma and rhinitis symptoms. The main outcome of this study will be specific airway resistance. The investigators will look for an association between specific airway resistance and vitamin D concentration measured during the first trimester of pregnancy in their mothers.
Study Type
OBSERVATIONAL
Enrollment
142
Lung plethysmography
Armand Trousseau Hospital
Paris, Paris, France
Necker Enfants-malades Hospital
Paris, Paris, France
Robert Debré Hospital
Paris, Paris, France
Specific airway resistance measured by plethysmography
The measure of this outcome will be compared between children with a concentration of vitamin D during the first trimester of pregnancy \< 20 ng/ml and children with a concentration ≥ 20 ng/ml
Time frame: 1 day
Interrupter airway resistance measured by the interrupter technique using a pneumotachograph
This secondary outcome is another way to measure airway resistance. The measure of this outcome will be also compared between children with a concentration of vitamin D during the first trimester of pregnancy \< 20 ng/ml and children with a concentration ≥ 20 ng/ml
Time frame: 1 day
Residual functional capacity measured by the helium dilution technique
This secondary outcome is another lung function parameter that will allow to evaluate lung volumes of the participants. The measure of this outcome will also be compared between children with a concentration of vitamin D during the first trimester of pregnancy \< 20 ng/ml and children with a concentration ≥ 20 ng/ml
Time frame: 1 day
Occurrence of one wheezing episode
Time frame: 1 day
Age of the first wheezing episode
Time frame: 1 day
Occurrence of Asthma at age 3 years old
Time frame: 1 day
Occurrence of Asthma at age 5 or 6 years old
Time frame: 1 day
Allergenic sensitizations determined by skin prick-tests
Time frame: 1 day
Genotype of 4 single nucleotide polymorphisms related to vitamin D metabolism
Time frame: 1 day
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