Background
Delivery of a premature baby is increasingly common. Premature delivery (defined as <37 completed gestational weeks) has been linked with increased chances of the mother developing diabetes and conditions affecting heart and blood vessels in later life. However, we do not yet know how strong this link is or why there is a link. In addition, there are no clear recommendations on how to follow-up women who had preterm birth.
Purpose
This study will assess how strong the link is between giving birth prematurely and developing heart disease and diabetes in the future. We will use routinely collected health information from the Clinical Practice Research Datalink to understand whether women with preterm birth are more likely to have heart disease and diabetes, and if so, is this because of the preterm birth itself or because of their background health risk factors before the pregnancy.
Potential importance of findings
This study will help to improve the health of women after preterm birth by identifying the factors that are linked to any increased risk of diabetes and heart and blood vessels disease. It may then be possible to reduce these health risks by giving advice to at-risk women.
Background
Some studies have linked preterm birth with future risks of cardiovascular disease and diabetes (cardio-metabolic diseases). However, it remains unclear whether preterm birth is an independent risk factor for future cardio-metabolic diseases or an early marker of women with high-risk factors for developing these diseases.
Objective
To assess whether preterm birth is an independent risk factor for long-term cardio-metabolic diseases.
Methods
Using a comparative cohort design, we will compare women with and without preterm birth (exposure), who had singleton pregnancies between 1997 and 2006. They will be followed for long-term cardio-metabolic diseases until incident event, end of 2016, last data collection or until they no longer contribute to CPRD due to leaving practice, death, or the practice leaving CPRD.
Data analysis
The baseline cardio-metabolic risk factors will be compared between women with and without preterm birth, using Chi-squared tests for categorical variables and t-tests for continuous variables. The independent associations between preterm birth and long-term cardio-metabolic diseases will be investigated using Cox proportional hazards model, adjusting for other potential risk factors. We will then assess differences in strength of the association of other risk factors with cardio-metabolic diseases between women with preterm and term births using interaction terms.
1) Coronary heart disease, defined as consultation for coronary heart disease, myocardial infarction, or coronary revascularization.
(2) Stroke, defined as consultation for stroke or transient ischaemic attack.
(3) Composite cardiovascular disease, defined as consultation for hypertension, coronary heart disease, myocardial infarction, coronary revascularization, heart failure, cardiomyopathy, stroke, transient ischaemic attack or peripheral vascular disease.
(4) Diabetes, defined as consultation for diabetes; prescription for antidiabetic antidiabetic (e.g. insulin, glibenclamide, metformin); and abnormal glucose tolerance test, fasting glucose or glycosylated haemoglobin.
(5) Mortality.
Pensee Wu - Chief Investigator - Keele University
Pensee Wu - Corresponding Applicant - Keele University
Carolyn Chew-Graham - Collaborator - Keele University
Claire Lawson - Collaborator - University of Leicester
Kelvin Jordan - Collaborator - Keele University
Mamas Mamas - Collaborator - Keele University
Umesh T Kadam - Collaborator - Keele University
CPRD Mother-Baby Link;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Pregnancy Register