Nicholas A. Christakis

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BACKGROUND The prevalence of obesity has increased substantially over the past 30 years. We performed a quantitative analysis of the nature and extent of the person-to-person spread of obesity as a possible factor contributing to the obesity epidemic. METHODS We evaluated a densely interconnected social network of 12,067 people assessed repeatedly from(More)
OBJECTIVES To evaluate whether happiness can spread from person to person and whether niches of happiness form within social networks. DESIGN Longitudinal social network analysis. SETTING Framingham Heart Study social network. PARTICIPANTS 4739 individuals followed from 1983 to 2003. MAIN OUTCOME MEASURES Happiness measured with validated four item(More)
centered on a large database, but in this case it is entirely of living organisms, the marine bivalves. Over 28,000 records of bivalve genera and subgenera from 322 locations around the world have now been compiled by these authors, giving a global record of some 854 genera and subgenera and 5132 species. No fossils are included in the database, but because(More)
BACKGROUND The prevalence of smoking has decreased substantially in the United States over the past 30 years. We examined the extent of the person-to-person spread of smoking behavior and the extent to which groups of widely connected people quit together. METHODS We studied a densely interconnected social network of 12,067 people assessed repeatedly from(More)
Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. It is known that individuals near the center of a social network are likely to be infected sooner during the course of an outbreak, on average, than those at the periphery. Unfortunately, mapping a whole network to identify(More)
The use of networks to integrate different genetic, proteomic, and metabolic datasets has been proposed as a viable path toward elucidating the origins of specific diseases. Here we introduce a new phenotypic database summarizing correlations obtained from the disease history of more than 30 million patients in a Phenotypic Disease Network (PDN). We present(More)
I reflect on the statistical methods of the Christakis-Fowler studies on network-based contagion of traits by checking the sensitivity of these kinds of results to various alternate specifications and generative mechanisms. Despite the honest efforts of all involved, I remain pessimistic about establishing whether binary health outcomes or product adoptions(More)
Human populations are both highly cooperative and highly organized. Human interactions are not random but rather are structured in social networks. Importantly, ties in these networks often are dynamic, changing in response to the behavior of one's social partners. This dynamic structure permits an important form of conditional action that has been explored(More)
CONTEXT A clear understanding of what patients, families, and health care practitioners view as important at the end of life is integral to the success of improving care of dying patients. Empirical evidence defining such factors, however, is lacking. OBJECTIVE To determine the factors considered important at the end of life by patients, their families,(More)
OBJECTIVE The purpose of this study was to characterize response rates for mail surveys published in medical journals; to determine how the response rate among subjects who are typical targets of mail surveys varies; and to evaluate the contribution of several techniques used by investigators to enhance response rates. METHODS One hundred seventy-eight(More)