Kathrine Agergård Kaspersen

Combined oral contraceptives are associated with higher levels of blood platelets among healthy women: results from the Danish Blood Donor Study (DBDS)

Publikation: KonferencebidragKonferenceabstrakt til konferenceForskningpeer review

Background Combined oral contraceptives (OC) are used by 27% of women aged 15-49 years in Denmark. OC offers convenient, effective and reversible fertility regulation, but the increased risk of venous thromboembolism, myocardial infarction, and ischemic stroke is the most important safety issues. Studies have investigated metabolic, proinflammatory, and haemostatic effects of estrogen and progestins contained in OC, meanwhile the impact of OC on blood platelet levels remains unknown. Aim: The aim of this study was to examine the impact of OC on the levels of blood platelets and haematocrit in a large cohort of blood donors. Methods Blood platelets levels in 28,950 women from The Danish Blood Donor Study giving blood in 2011-2016 in the Capital and Central Danish Regions were measured by automated haematology analysers at each donation. All participants completed a standard questionnaire on lifestyle factors and further stated their use of contraception, childbirth, and menopausal status. OC exposure period and type of OC were identified by ATC codes in the Danish National Prescription Registry. The association between OC and blood platelet levels was explored by repeated measures mixed model analysis. Adjustment for age and time since last donation was performed. Results are presented as coefficients with 95% confidence intervals (CI). Results A total of 9,327 (32.2%) participants filled an OC prescription in the study period, of whom 5,821 (20.1% of women) were intermittent OC users and 3,506 (12.1% of women) were continuous OC users. Among users, 559 (2.7%), 5,552 (26.8%), 12,447 (60.0%) and 2.172 (10.5%) were users of 1st, 2nd, 3rd, and 4th generation of OC, respectively. Blood platelet levels were higher among OC users compared to non-users (coef: 9.7 billion thrombocytes/L, CI: 9.2-10.2, p<0.001). The difference was increased when comparing OC continuous users vs. non-users (coef: 18.5, CI: 16.4-20.6, p<0.001) although the difference between OC intermittent users vs. non-users (coef: 10.2, CI: 8.5-11.9, p<0.001) was the same as for OC users vs. non-users. There was no difference between OC types in their effect on blood platelet levels. Conclusion OC users had higher levels of blood platelets than non-users. The findings are very important to help understand the effect of OC on risk of thromboembolism. The underlying mechanism of OC on blood platelets needs further investigation. Our finding underscores that blood donor cohorts are feasible for the study of health properties in healthy persons.
Udgivelsesår4 jun. 2018
StatusUdgivet - 4 jun. 2018
Begivenhed35th International Congress of ISBT, Toronto - Metro Convention Centre, Toronto, Canada
Varighed: 2 jun. 20186 jun. 2018


Konference35th International Congress of ISBT, Toronto
LokationMetro Convention Centre

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