Perinatal Stress, Nutrition, and Risk of Respiratory Symptoms in Offspring of Mexican Women: Results of a Pilot Study

Background. Factors responsible for the relatively low risk of asthma in Mexico-born Mexican American (MA) children remain poorly understood. Previous studies suggest that perinatal nutrition and stress may play a role in the development of asthma, but studies assessing the joint effect of both factors on the risk of asthma are scarce.

Purpose. 1) Determine the feasibility of (a) recruiting pregnant women of Mexican descent, and (b) obtaining completed questionnaires and biological samples (saliva and hair samples for cortisol; blood samples for vitamins D/E); and 2) Determine the acceptability of the study procedures and data collection approaches.

Methods. We will recruit 30 self-identified Mexican/MA women 18-40 years of age before their 17th week of gestation. The inclusion criteria include: 1) Singleton pregnancy, and 2) Able to communicate in English and/or Spanish. Exclusion criteria include: 1) Multiple gestation; and 2) Conditions that interfere with dietary intake during pregnancy. Data will be collected at baseline, 26-32 weeks of gestation, and 2-8 weeks postpartum. We will obtain data on maternal personal characteristics, stress, diet, and other covariates. We will also collect blood samples for assessment of serum levels of vitamin D (25-hydroxyvitamin D) and vitamin E (alpha-tocopherol). Salivary samples for measurement of cortisol as a biomarker of stress will be collected at T2 while hair samples (for cortisol assessment) and information on birth outcomes and other variables will be obtained at T3.  

Results. Nineteen women have been enrolled as participants. Five women approached refused to participate, citing busy work schedules and time constraints. Our enrollment rate is 79% (19 enrolled participants/24 eligible participants). Currently no enrolled participants have withdrawn from the study, declined to participate, or been lost to follow up; this includes 1 participant who completed all time periods, while all others being followed for several months. On average, 7 phone calls per participant are made for appointment scheduling and questionnaire collection.

Conclusion. Preliminary results suggest this study is feasible with regards to recruitment, retention, and data collection efforts. This study represents an essential first step for conducting a large-scale longitudinal study on effects of perinatal stress and diet on the risk of asthma.