Seppo Sarna

Diagnosis of Twin Zygosity by Mailed Questionnaire

A deterministic questionnaire method for zygosity determination is developed for use in epidemiological studies of adult twins. It is based on the answers of both members of a twin pair to two questions on similarity and confusion in childhood. The algorithm of the method is used to determine the zygosity status of a twin pair at two different levels of certainty. The validity of the method is tested by making blood marker determinations of 11 polymorphic marker systems fro a random sample of 104 twin pairs. The agreement between questionnaire and blood marker diagnosis was 100%, but the stricter level of certainty left 8.7% in the nonclassified group. The genetical representativeness of the sample is tested by the allele distribution of the markers as compared to the Finnish population data as well as by the distribution of the number of intra-pair differences in blood markers.

Differences in mortality from Ischemic Heart Disease by marital status and social class

Abstract IHD mortality and psychosocial factors were studied by analyzing IHD mortality rates, by marital status and social class simultaneously. Standardized death rates were calculated for all IHD deaths (32,433) in Finland among 25–84-yr-olds during a 3-yr period. The reliability of the IHD diagnostics was evaluated by studying autopsy rates, criteria for the IHD diagnosis, the proportional mortality rate of IHD with respect to other heart diseases and total disease mortality, and geographical factors. In different marital-status-social-class combinations, the proportion of deaths from IHD was highest when total disease mortality was lowest. The variation with marital status or social class, separately, was less than when both factors were analyzed simultaneously. The highest IHD mortality was concentrated among widowed and divorced unskilled workers, the differences between marital status and social class being most marked (3.3-fold) for men aged 25–54. Divorced and widowed persons seemed to have a higher risk of sudden death than married persons. The Finnish east-west difference in IHD mortality accentuated differences by marital status and social class, in particular a high-risk group—widowed unskilled workers—having a seven-fold mortality risk compared to the whole of North Karelia, an area of high IHD mortality.

Social factors and the gender difference in mortality

The effect of social factors on the male/female difference in mortality in Finland was studied by comparing age-adjusted mortality of males and females by social class and marital status. 44,548 death certificates (years 1969-1971) and 1970 census data for 25-64-years olds were analysed. The gender difference was 2.8-fold: 5.3-fold for violent causes and 2.3-fold for natural causes. The greatest gender difference from violent causes was found in accidental poisonings (18.7-fold) and drownings (12.8-fold), and from natural causes in mental disorders (mainly alcoholism; 5.7-fold) and in ischemic heart disease (4.5-fold). The gender difference was most prominent in unskilled workers, divorced and widowed and less prominent in married and upper professionals. The great variation of gender difference of mortality by social class and marital status seems to indicate that mortality difference between males and females is associated to external factors rather than biological differences between men and women. This conclusion is also supported by the progressive increase of gender difference of mortality from 1.4 to 2.8 during the last 80 years in working-aged Finns.

Character of Urinary Tract Infections and Pyelonephritic Renal Scarring After Antireflux Surgery

We followed 40 girls who had undergone antireflux surgery (the Politano-Leadbetter technique) at the mean age of 5.2 years until they reached a mean age of 9.5 years. Each girl was matched with a control. The pairs were matched for age at the onset of urinary tract infections and time of operation or selection, number as well as grade (1 to 3) of severity of the preoperative episodes and grade (II to IV) of reflux. Followup time for each member of the pair was identical. Postoperatively, the incidence of pyelonephritic urinary tract infection episodes (grade 3) was significantly less (p less than 0.01) among the operated than the nonoperated cases (9 versus 29), while the number of symptomatic lower urinary tract infections (grade 2) was virtually the same (14 versus 19) in both groups. The operated cases had more asymptomatic bacteriuria (26 versus 12 episodes) so that the total numbers of episodes of bacteriuria (grades 1 through 3) were similar in both groups. Antireflux surgery did not prevent the progression of pyelonephritic renal scarring, which continued equally in operated and nonoperated cases.

Psychosocial and environmental correlates of coronary-prone behavior in Finland☆

Coronary-prone behavior pattern was studied in a Finnish population sample consisting of 11364 adults (5419 males and 5945 females). A questionnaire-based short rating scale developed by Bortner was used. The distribution of the study population on the A-B axis was unimodal with no distinctive grouping into A- and B-types. Age-specific mean scores were highest in 30–40 yr olds. The highest and lowest deciles were designated to represent type A and type B respectively. n nA-type men were more often married, self-employed or in white collar work, and had larger incomes and more changes of residence. A-type persons were more extrovert and their life satisfaction was greater. A-type men slept less on average than B-type men. A-type persons experienced their daily activities more tiring, but their work less monotonous. A-type persons used spirits a little more often and smoked slightly more cigarettes. B-type persons spent more time on leisure-time physical activity, both the time spent per session and the frequency of sessions being greater. n nIn this cross-sectional study the A-type men reported more often a history of myocardial infarction diagnosed by a physician (2.0 vs 0.6%, ns) and severe chest pain in the Rose questionnaire (8.7% vs 5.3%, p < 0.05) compared to the B-type men, as well as a higher prevalence of Rose-positive angina pectoris (7.5% vs 5.7%, ns). The study cohort is being followed-up for incidence of coronary heart disease events and mortality.

Use of Multiple Logistic Analysis in Twin Zygosity Diagnosis

Stochastic methods were applied to the diagnosis of twin zygosity by mailed questionnaire in a study on adult twins. Multiple logistic discriminant analysis was able to classify twin pairs previously left unclassified (XZ) by a deterministic method, and accuracy of classification was verified by blood testing. The mean intrapair differences of height and weight of XZ pairs were in between dizygotic and monozygotic pairs, but the frequency of personal contact between XZ twins was significantly less than that of MZ or DZ pairs. Both classification methods, when used separately with the same questions, left unclassified 6.5-7.6% of all 11,542 respondent pairs in the Finnish Twin Registry, but deterministic classification followed by logistic analysis misclassified only 1.9% of all twin pairs.

Cause-specific mortality by marital status and social class in Finland during 1969–1971

Abstract Variation in cause-specific mortality by marital status and social class in Finland during 1969–1971 was studied. Greatest variations were found for violent deaths, infectious diseases and alcohol-associated diseases. If other factors were kept constant, elimination of differences in mortality by social class would reduce total mortality by 21%. The corresponding figure for marital state differences would be 13%. However, differences in mortality rates between marital status categories were greater than between social class categories. It was concluded that both selective forces and environmental factors influence these mortality differences, but further clarification should be based on prospective studies of life-changes, environmental factors and morbidity.

Health related psychosocial correlates of neuroticism: a study of adult male twins in Finland

Some health related psychosocial correlates of the Eysenck neuroticism scale were examined in a questionnaire study of 1501 monozygotic (MZ) and 3455 dizygotic (DZ) male twin pairs representing the adult male twin population in Finland. In analyses of the individuals, 34% of the variance in neuroticism was associated to: psychological variables (stress of daily activities, life satisfaction, quality of sleep, and extroversion - the explanatory rate of this variable set was 30%), psychotropic drugs (5%), alcohol use (4%), and smoking (2%). Neuroticism was also associated to social, life change, and medical variables. In pairwise analyses, the heritability estimate (h2) was 0.54 for pairs living together and 0.39 for pairs living apart. It seems that heritability estimates are confounded by the closer intrapair relationship between members of MZ than DZ pairs. In pairwise analyses, 23% of the intrapair difference of neuroticism in MZ pairs was associated to intrapair differences in the aforementioned variables. The following explanatory rates were found: psychological variables, 21%; psychotropic drugs, 2%; alcohol use, 2%; and smoking, 1%. Neuroticism of pairs discordant for background variables showed similar intrapair differences as between individuals in the following variables: service vs farming work, use of alcohol, use of antacids, hypertension, heavy physical work, quality of sleep, changes of workplace for negative reasons, smoking, and use of tranquillizers. It appears that in Finland environmental factors explain at least 61% of the variability in neuroticism, and that factors determining neuroticism are also associated to health related behavior such as smoking, use of alcohol and psychotropic drugs.

The Role of Vesicoureteral Reflux in Paediatric Urinary-Tract Infection

Observations are reported from a series of 284 children, 68 boys and 216 girls, who had had one or more episodes of urinary tract infection (UTI) and had vesicoureteral reflux (VUR) of grade II, III or VI. In 6 of the boys and 43 of the girls the Politano-Leadbetter operation for correction of VUR was performed. Only in grade III or IV VUR was the cure rate--considered solely as cessation of reflux--significantly higher in surgically than in non-surgically treated children. Irrespective of sex or mode of treatment, the number of episodes of UTI tended to diminish as the children grew older. For more precise comparisons, two individually matched groups of 40 girls were studied. One girl in each pair was operated on. Within these matched pairs, the frequency of UTI episodes according to age did not differ appreciably. Nor did the number of UTI episodes before and after the time of operation differ significantly when analysis was made according to grade of reflux. Thus, although disappearance of surgically treated grades III and IV VUR was more rapid and more frequent than spontaneous cessation of reflux, the observations in the matched pair series indicated that antireflux surgery does not affect the incidence of UTI.

Mortality Rates after Multifactorial Primary Prevention of Cardiovascular Diseases

Eleven-year mortality rates were studied in middle aged men who had participated in a randomised 5-year multifactorial primary prevention trial on cardiovascular diseases during 1974-1980. The men were given health education advice before the study. The 5-year trial markedly improved the risk factor status in the men in the intervention group (n = 612), but their 5-year incidence of total coronary events tended to be higher than in the randomised non-treated control group (n = 610) and significantly higher than in an non-randomised, non-treated low risk group (n = 593). During the six years following the discontinuation of the trial, 11 deaths from cardiovascular disease occurred both in the intervention and in the control groups and three in the non-randomised low risk group. Thus, the cumulative eleven-year cardiovascular mortality rates and their 95% confidence intervals (Cl95) were 2.45% (Cl95: 1.38, 3.67) in the intervention group and 1.97% (Cl95: 1.01, 3.34) in the randomised high risk control group. In the non-randomised low risk group the mortality rate was 0.51 (Cl95: 0.01, 1.46). Multiple logistic regression analysis showed that overweight and hypercholesterolaemia, and smoking in the high risk controls, were the initial risk factors associated with the 11-year cardiovascular mortality. The latter was not accumulated in any treatment measure during the prevention period. Furthermore, despite the unfavourable effect of beta-blocking agents on total cardiac events during the intervention, beta-blockers were not associated with cardiac deaths in the 11-year follow up.(ABSTRACT TRUNCATED AT 250 WORDS)