Season of Birth and Cardiovascular Mortality in Atrial Fibrillation: A Population-Based Cohort Study

Background: The fetal origins hypothesis have associated early life exposures with the development of adverse health outcomes in adulthood. Season of birth has been shown to be associated with overall and cardiovascular mortality. Methods: We performed a retrospective database study to explore the association between season of birth and mortality in patients with atrial fibrillation. Results: A total of 8962 patients with AF were identified in the database with 1253 deaths recorded. AF patients born in spring and summer had a higher mortality rate when compared to those born in autumn and winter (hazard ratio (HR) 1.13, 95% confidence interval (CI) 1.01–1.26, p = 0.03). This effect was consistent in the male subgroup (HR 1.25, 95% CI 1.03–1.51, p = 0.02 for males born in spring; HR 1.24, 95% CI 1.03–1.51, p = 0.03 for males born in summer when compared to winter as the reference) but not in females (HR 1.02, 95% CI 0.79–1.31, p = 0.88 for females born in spring; HR 1.11, 95% CI 0.87–1.42, p = 0.39 for females born in summer when compared to winter as the reference). Results persisted after adjustment for baseline characteristics and clinical risk profile. A similar pattern was observed with cardiovascular mortality. Conclusion: Birth in spring or summer is associated with a higher risk of cardiovascular mortality in male AF patients, but not in females. This could be related to the underlying differences in rates of major adverse clinical events between genders. Further studies should aim at clarifying the mechanisms behind this association, which may help us understand the higher level of risk in female patients with AF.

FETAL ORIGIN OF ADULT DISEASE

“Fetal origins of adult disease”, often called the “Barker hypothesis” after a large proportion data of Barker and colleagues in Southampton over the last decade, that adverse influences early in development, and particularly during intrauterine life, can result in permanent changes in structure, physiology, metabolism, which result in increased disease risk in adulthood. Many further studies have provided evidence for the hypothesis that size at birth is related to the risk of developing disease in later life. In particular, links are well established between reduced birthweight and increased risk of coronary heart disease, diabetes, hypertension and stroke in adulthood. The most widely accepted mechanisms thought to underlie these relationship are those of altered fetal nutrition, genetic–epigenetic links, fetal programming and fetal excess glucocorticoid exposure. It is suggested that the fetus makes physiological adaption in response to changes in its environment to prepare itself for posnatal life. The “Fetal origin of adult disease” hypothesis is attractive. It suggests that these diseases could be prevented by improving maternal health and fetal development

Season of birth and cardiovascular mortality in atrial fibrillation: a population-based cohort study

Funding Acknowledgements Type of funding sources: None. Background. Month and season of birth may be indicators for a variety of prenatal and early postnatal exposures and they have been associated with life expectancy in adulthood. It is suggested that people born in the autumn on the northern hemisphere live longer than those born during the spring or summer, who may have an increase in cardiovascular disease specific mortality. Only few studies have followed populations longitudinally and no study has investigated the relation between season of birth and mortality in patients with established cardiac conditions. Methods. All patients with atrial fibrillation (AF) seen in an academic institution were identified in a database. We examined the clinical course of 8962 consecutive patients with AF seen over a 10-year period. The adverse outcomes were investigated during follow-up and we identified the causes of death. The relation between season of birth (autumn, winter, spring and summer) and mortality risk was assessed using Cox proportional hazard regression models using autumn as the reference. Analyses were also made separately for men and women. Results. In these 8962 patients (age 70 ± 10 years, CHA2DS2VASc score 3.1 ± 1.7), 1253 deaths were recorded during a follow-up of 2.5 ± 3.0 years (median 1.2, interquartile 4.3 years, yearly rate of death 5.5%) and 97% of causes of death were identified. Cardiovascular deaths accounted for 54% and 43% for non-cardiovascular. The three main causes of death were heart failure (29%), infection (18%) and cancer (12%). Season of birth was a significant predictor of cardiovascular mortality (overall p = 0.0006). The lowest mortality was seen for people born in autumn or winter and the highest mortality in those born in spring and summer. This was mainly related to a higher cardiovascular mortality in males (hazard ratio [HR] 1.46, 95%CI 1.10-1.93, p = 0.009 for males born in spring and HR 1.44, 95%CI 1.08-1.91, p = 0.01 for those born in summer when compared to males born in autumn as the reference) while this effect was not seen in women. In a model adjusted for age, CHA2DS2VASc score, HASBLED score, cardiovascular risk factors, other comorbidities, AF pattern, antithrombotic use and other cardiovascular drugs use, a higher cardiovascular mortality was still seen in males born in spring (adjusted HR 1.43, 95%CI 1.05-1.96, p = 0.03) or in summer (adjusted HR 1.46, 95%CI 1.07-1.99, p = 0.02) when compared to those born in autumn while this was not seen in women. Conclusion. Birth in spring or summer is associated with a higher risk of cardiovascular mortality in male AF patients. Further studies should aim at clarifying the mechanisms behind this association, which would support the so-called fetal origins hypothesis.

The Fetal Origins of Human Psychological Development

The human fetus holds the key to unlocking the initial origins and predispositions of all aspects of human psychological development. Despite this, difficulties related to experimentally manipulating the behavior of the fetus to assess capacities have sidelined the fetus within the developmental sciences. Instead, the focus has been on the human infant. With new developments in the fields of obstetrics, medical physics, and psychology, the methodological constraints surrounding research on the human fetus are now reduced. We highlight new approaches and indicate possible new directions in the understanding of the cognitive and perceptual capacities of the human fetus.