%0 Journal Article %T Season of Birth and Exceptional Longevity: Comparative Study of American Centenarians, Their Siblings, and Spouses %A Leonid A. Gavrilov %A Natalia S. Gavrilova %J Journal of Aging Research %D 2011 %I Hindawi Publishing Corporation %R 10.4061/2011/104616 %X This study explores the effects of month of birth (a proxy for early-life environmental influences) on the chances of survival to age 100. Months of birth for 1,574 validated centenarians born in the United States in 1880¨C1895 were compared to the same information obtained for centenarians' 10,885 shorter-lived siblings and 1,083 spouses. Comparison was conducted using a within-family analysis by the method of conditional logistic regression, which allows researchers to control for unobserved shared childhood or adulthood environment and common genetic background. It was found that months of birth have significant long-lasting effect on survival to age 100: siblings born in September¨CNovember have higher odds to become centenarians compared to siblings born in March. A similar month-of-birth pattern was found for centenarian spouses. These results support the idea of early-life programming of human aging and longevity. 1. Introduction Studies of centenarians (persons living to age 100 and over) are useful in identifying factors leading to long life and avoidance of fatal diseases. These studies may be a sensitive way to find genetic, familial, environmental, and life-course factors associated with lower mortality and better survival [1, 2]. Several theoretical concepts suggest that early-life events and conditions may have a significant long-lasting effect on survival to advanced ages. These concepts include (but are not limited to) the idea of fetal origin of adult diseases also known as the Barker hypothesis [3, 4] and the related idea of early-life programming of aging and longevity; the theory of technophysio evolution [5], the reliability theory of aging, and the high initial damage load (HIDL) hypothesis in particular [6, 7]. These ideas are supported by the studies suggesting significant effects of early-life conditions on late-life mortality [3, 8¨C10]. Finch and Crimmins [11] suggested that historical decline in chronic inflammation (due to decreasing exposure to early-life infections) has led to a decrease in morbidity and mortality from chronic conditions at old age. They showed that both childhood mortality and cardiovascular diseases of old age may share common infectious and inflammatory causes rooted in the external environment [12]. Month of birth often is used by epidemiologists as a proxy characteristic for environmental effects acting during in-utero and early infancy development. These early effects include temperature and sun exposure during in-utero and early postnatal period, nutritional status during early development, exposure to %U http://www.hindawi.com/journals/jar/2011/104616/