Markku Heliövaara

Depression and cardiovascular diseases

We first review the asSociations between depression and cardiovascular diseases (CVDs). Then we examine them in the nationally representative Mini‐Finland Health Survey, which covers 8,000 persons. Chronic somatic diseases and mental disorders were diagnosed using standardized methods. Cross‐sectionally, CVDs and neurotic depression were asSociated both before and after adjustment for covariates. The strongest asSociations were observed in the case of severe CVDs. During a 6.6 year follow‐up, the risk of CVD death and coronary death was elevated in depressed persons both with and without CVDs at entry. Much of the cross‐sectional asSociation is probably due to depression caused by CVDs. The outcome of CVD may be poorer in depressed persons. The hypothesis that depression is a cause of CVDs requires further study.

Reliability and validity of interview data on chronic diseases The mini-Finland health survey

The Mini-Finland Health Survey was designed to obtain a comprehensive picture of health and of the need for care in Finnish adults, and to develop methods for monitoring health in the population as a whole. Out of a nationally representative sample of 8000 people aged 30 or over, 7217 (90%) were both interviewed at home by local public health nurses using simple open-ended questions and, independently of this interview, subsequently examined in a two-phase health examination. The estimate of chronic morbidity based on the health interview (56%) was close to the prevalence of definite somatic diseases diagnosed in the health examination (54%), and the agreement between the two methods was moderate (kappa = 0.53). The estimated prevalence of cardiovascular diseases was the same (23%) in the health interview and in the health examination; the agreement was substantial (kappa = 0.74). The prevalence of respiratory and musculoskeletal diseases and mental disorders was underestimated in the interview by 52, 25 and 78%, respectively; the agreement between results of the two methods was relatively low (kappa = 0.43, 0.38 and 0.30, respectively). These results suggest that both the health examination and the health interview methods, as used in this survey, have useful applications in monitoring the populations health.

Risk factors for subarachnoid hemorrhage in a longitudinal population study

The known risk factors of atherosclerotic diseases may be involved in the development of a subarachnoid hemorrhage. We studied the morbidity and mortality due to subarachnoid hemorrhage among 42,862 men and women aged 20-69 years who had participated in a large health survey in Finland. During a mean follow-up of 12 years, 102 non-fatal and 85 fatal cases of subarachnoid hemorrhage were observed. The total incidence was 37 per 100,000 person-years. Smoking and hypertension were positively associated and body mass index was inversely associated with the risk of subarachnoid hemorrhage. These associations were not confounded by age or each other. No statistically significant association with risk was detected for serum cholesterol level, hematocrit content, known heart disease, or diabetes. The risk was especially elevated among lean hypertensive subjects and lean smoking subjects. The age-adjusted relative risks of subarachnoid hemorrhage for lean, hypertensive smokers were 18.3 (95% confidence interval (CI), 7.8-42.7) among women and 6.7 (95% CI, 2.3-19.7) among men as compared to the risk among subjects without these risk factors. We conclude that modifiable risk factors are predictive of subarachnoid hemorrhage, for which reason subarachnoid hemorrhage may in part be preventable. Leanness combined with arterial hypertension and/or smoking, in particular, poses a substantially elevated risk.

Risk Factors for Low Back Pain and Sciatica

So far, eight prospective studies and 50 cross-sectional or retrospective studies have focused on risk factors for low back syndromes. Half of these have been published during the 1980s. Hard physical work and, in particular, frequent lifting and postural stress are likely to result in disc degeneration, low back pain and sciatica. Physical strain may also have prophylactic effects, as physical leisure activity and muscular strength are negatively associated with the risk of low back pain. Much evidence points to driving motor vehicles being causally associated with low back pain and sciatica. A probably causal relationship exists between body height and risk of sciatica, but height is not necessarily predictive of other types of low back pain. Obesity, smoking, psychological distress and poor general health also carry increased risk of low back pain, but their causal role is questionable. Although none of the suspected risk factors can be described as having been conclusively investigated epidemiologically, the results of published studies show that there are modifiable factors contributing to low back pain. The overall potential of primary prevention is great if adequate tools for intervention can be developed.

Occupation and risk of herniated lumbar intervertebral disc or sciatica leading to hospitalization

Various occupations were studied for the prediction of herniated lumbar intervertebral disc or sciatica in 592 men and women who had been discharged from hospital with these diagnoses during an 11-year follow-up after a health examination. The cases were compared with 2140 controls matched individually for sex, age and place of residence. Subjects who, at the initial examination before the follow-up, had reported a history of back pain or sciatica were excluded. In men, the risk of being hospitalized due to herniated lumbar disc or sciatica was lowest in professional and related occupations, significantly higher in all other groups and highest among blue-collar workers in industry and among motor vehicle drivers. The variation in the risk between occupational groups of women proved less but was nevertheless still apparent. However, in women, but not in men, the risk was significantly associated with self-assessed strenuousness of work.

Musculoskeletal disorders as determinants of disability in Finns aged 30 years or more

The relationship between disability and various musculoskeletal disorders was investigated in 7217 men and women representative of the Finnish population aged 30 years or more. They participated in the Mini-Finland Health Survey and were first screened by interview and questionnaire about limitations in daily activities. The outcome variables were reduced working capacity, an occasional need for assistance in daily activities, and a regular need for assistance in daily activities. In a two-phase medical examination, all cases fulfilling predetermined diagnostic criteria of musculoskeletal, cardiovascular, respiratory and mental disorders and diabetes were recorded independently. In multivariate logistic regression analyses, inflammatory arthritis was the strongest determinant of all forms of disability. Osteoarthritis, especially in the hip, was a strong determinant of both occasional and regular need for assistance, and chronic low back pain was a strong determinant of reduced working capacity and occasional need for assistance among those aged 30-64 years. Other musculoskeletal disorders also determined the prevalence disability, but these relationships were reduced by taking comorbidity into account. A low level of education and a low (less than 20 kg/m2) or very high (at least 35 kg/m2) body mass index represented independent determinants of all forms of disability, and a history of physically strenuous work an independent determinant of reduced working capacity, when disabling illness was adjusted for. The proportion of all forms of disability attributable to musculoskeletal disorders, in models including, age, sex, other disabling illness and significant non-medical determinants of disability, was close to 20%. The disorders with the highest community impact were chronic low back pain among those aged 30-64, osteoarthritis of the hips and knees and inflammatory arthritis.

Association of overweight, trauma and workload with coxarthrosis: A health survey of 7,217 persons

In a population sample health survey, body mass, previous trauma and physical stress were studied for associations with coxarthrosis. A sample of 8,000 persons representative of the Finnish population aged 30 or over was invited for examination, and 90 percent participated. On the basis of a standardized clinical examination, a physician diagnosed coxarthrosis in 6 percent of the women and 4 percent of the men. The prevalence rose with age. In persons with a past traumatic lower-limb injury, the odds ratio of unilateral coxarthrosis was 2.1 and of bilateral coxarthrosis 1.5, as adjusted for sex, age and other determinants using logistic regression. The sum index reflecting self-reported features of physical stress in present or previous occupations was directly proportional to the prevalence of coxarthrosis. Body mass index (kg/m2) was closely associated with bilateral coxarthrosis; the adjusted odds ratio (95 percent confidence intervals) for indices > 35, compared to those < 25, was 2.8 (1.4-5.7). In terms of the population attributable fraction, prior trauma, physical stress and body mass were estimated to explain 59 percent of the prevalence of coxarthrosis. The potential for primary prevention may be great, but longitudinal population studies are necessary to elucidate causal significance of the risk factors.

Incidence and risk factors of herniated lumbar intervertebral disc or sciatica leading to hospitalization.

Hospital admissions for herniated lumbar intervertebral disc or sciatica were followed up over a period of 11 years in 57,000 men and women who had participated in medical check-ups in various parts of Finland. Information on their hospitalizations after the baseline examination was obtained by record linkage to the National Hospital Discharge Register. To identify factors predicting back diseases, four controls matched individually for sex, age and place of residence were chosen for each of the 592 incidence cases who were free from severe back trouble and aged 20-59 at entry. Low or intermediate social class and blue-collar occupations in services or industry in men and symptoms suggesting psychological distress in women proved significant predictors for hospitalization due to herniated lumbar disc or sciatica. An association with the risk was suggested for smoking or chronic cough in men and parity in women. Marital status or leisure time physical activity were not predictive of herniated lumbar intervertebral disc or sciatica.

Serum cholesterol and risk of cancer in a cohort of 39,000 men and women

Serum cholesterol concentration was studied for its prediction of cancer in 39,268 men and women aged 15-99 years and initially free from cancer. During a median follow-up of 10 years 1381 cancer cases were diagnosed. Serum cholesterol level was inversely associated with cancer incidence among non-smokers. Age-adjusted relative risks of cancer in quintiles of serum cholesterol were in male non-smokers 1.0, 0.81, 0.73, 0.69, and 0.46 and in female non-smokers 1.0, 0.75, 0.84, 0.78, and 0.70. The associations were not found to be confounded by serum vitamins A or E, serum selenium or several other factors. The association between serum cholesterol level and risk of cancer varied from strongly negative to slightly positive according to subpopulation and site of cancer. The strongest negative associations were found to appear during the first years of follow-up, especially for rapidly developing cancers. Thus the increased occurrence of cancer at low cholesterol levels seems mainly to be due to preclinical cancer.

Genetic and Environmental Factors in Sciatica Evidence from a Nationwide Panel of 9365 Adult Twin Pairs

The relative roles of genetic and environmental factors in sciatica were studied in the nationwide Finnish twin panel consisting of 9365 adult pairs of the same gender. Morbidity was analysed from two sources of data: the life-long cumulative incidence was measured by a postal questionnaire, and the rate of hospital admission during a 14-year period was measured by record-linkage of the twin panel and the nationwide hospital registry. Altogether 2220 individuals reported sciatica diagnosed by a doctor and 304 were admitted to hospital with a diagnosis of sciatica. The proportion of concordant pairs (calculated from affected pairs) was 17.7% for monozygotic and 12.0% for dizygotic pairs in the life-long cumulative incidence of reported sciatica, and correspondingly 4.6% and 1.9% for those admitted to hospital (a 14-year period) because of sciatica. The estimated heritability was 20.8% for those with reported sciatica and 10.6% for those admitted to hospital. The results show that environmental factors account for more than 80% of the etiology of sciatica, and more than 90% in the case of patients admitted to the hospital. Genetic factors, however, were relatively more significant in individuals under 40.