An opinion has existed for many years that, on the average, married persons live longer than those who are single, and particularly that married men live longer than single men; but it has been rather difficult to secure data to establish this conclusion. The age classifications of censuses and of state departments of health have often been defective in the material necessary for definite conclusions, and besides, too few age classifications were made. The federal censuses of 1890 and 1900, for instance, were of little value for this study because the age classifications, 15 to 44, 45 to 64, and 65 and over, gave small opportunity for comparative mortality. Age and sex have so much influence on mortality that the effect of each of these must be eliminated before the possible effect of the marriage state on the death-rate can be determined. The comparison to be of value for statistical purposes and for conclusions as to health and life-expectancy must be between the death-rates of persons of the same sex and age, but of different marital conditions.
Comparative Mortality of Married and Single Persons. JAMA. 2013;310(3):326. doi:10.1001/jama.2013.5212