Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: Results from studies of twin concordance in multiple sclerosis have not conclusively differentiated between environmental and genetic factors that determine susceptibility to the disease. Published studies that have been based on case finding by public appeal have been characterized by difficulties in ascertainment. The data reported here are from a large population-based study of multiple sclerosis in twins, in which ascertainment has been relatively unbiased and the cooperation of patients nearly complete. A total of 5463 patients attending 10 multiple sclerosis clinics across Canada were surveyed. Twenty-seven monozygotic and 43 dizygotic twin pairs were identified, and the diagnosis of multiple sclerosis was verified by examination and laboratory investigation. Seven of 27 monozygotic pairs (25.9 percent) and 1 of 43 dizygotic pairs (2.3 percent) were concordant for multiple sclerosis. The concordance rate for 4582 nontwin siblings of patients at two multiple sclerosis clinics was 1.9 percent, closely paralleling the concordance rate in dizygotic twins. To the extent that the difference in concordance rates between monozygotic and dizygotic twins indicates genetic susceptibility, the results of this study show a major genetic component in susceptibility to multiple sclerosis.
Canada

Abstract: A national survey of pain in the United States has been conducted, using a sample of 1254 persons 18 years of age or more, statistically constructed so as to permit projections to be made to the entire adult population of 174 million with a predicted accuracy of +/- 2-3%. Pain prevalence and severity, and its impact on work and other activities were obtained and correlated with demographic variables. This paper reports the portion of the study examining the association of pain with stress, daily hassles, measures of health locus of control, and various health habits. There was a very strong association between stress and pain and hassles and pain. The greater the stress and hassles, the greater the incidence, frequency and severity of all pains reported. Those with high internal health locus of control are more likely to have healthy behavior, are less likely to have all kinds of pain, and have less severe pain. Stress was voluntarily mentioned by respondents as a major cause of pain in headaches, backaches, stomach pains, and menstrual pains, but not for muscle, joint or dental pains.
Adult

Abstract: Previous serial measurements of lymphocyte subpopulations in individuals with multiple sclerosis (MS) have demonstrated periodic reductions in the number of OKT8 positive (T8+) cells. In this longitudinal study, involving twice monthly samples from each participant and carried out in two phases lasting at least six and three months respectively, we have confirmed that fluctuations in T8+ cells occur in patients with MS and also found a significant reduction in this lymphocyte subpopulation in patients' spouses but not their siblings, compared with unrelated controls. The changes observed in spouses were related in time to those occurring in patients on 10/13 occasions from 5/9 families; no temporal relationship occurred in the remainder. Taking two or more low T8+ values as significant, 12/13 patients, 7/9 spouses, 6/13 siblings and 4/13 controls (chi 2 = 12.5; P less than 0.01) were abnormal at some stage. Our results provide indirect evidence for the role of environmental factors in determining certain immunological abnormalities present in patients with MS and illustrate the role of family studies in determining the specificity of these changes to the disease.
Adult