Simo Näyhä

Heat related mortality in warm and cold regions of Europe: observational study

Abstract Objectives: To assess heat related mortalities in relation to climate within Europe. Design: Observational population study. Setting: North Finland, south Finland, Baden-Württemberg, Netherlands, London, north Italy, and Athens. Subjects: People aged 65-74. Main outcome measures: Mortalities at temperatures above, below, and within each regions temperature band of minimum mortality. Results: Mortality was lowest at 14.3-17.3°C in north Finland but at 22.7-25.7°C in Athens. Overall the 3°C minimum mortality temperature bands were significantly higher in regions with higher than lower mean summer temperatures (P=0.027). This was not due to regional differences in wind speeds, humidity, or rain. As a result, regions with hot summers did not have significantly higher annual heat related mortality per million population than cold regions at temperatures above these bands. Mean annual heat related mortalities were 304 (95% confidence interval 126 to 482) in North Finland, 445 (59 to 831) in Athens, and 40 (13 to 68) in London. Cold related mortalities were 2457 (1130 to 3786), 2533 (965 to 4101), and 3129 (2319 to 3939) respectively. Conclusions: Populations in Europe have adjusted successfully to mean summer temperatures ranging from 13.5°C to 24.1°C, and can be expected to adjust to global warming predicted for the next half century with little sustained increase in heat related mortality. Active measures to accelerate adjustment to hot weather could minimise temporary rises in heat related mortality, and measures to maintain protection against cold in winter could permit substantial reductions in overall mortality as temperatures rise.

Physical activity and social status in adolescence as predictors of physical inactivity in adulthood

BACKGROUND Physical inactivity is related to an increased risk of certain chronic diseases. The aim here was to evaluate how physical activity and social status in adolescence are associated with physical inactivity in adulthood. METHODS The sample comprised 3664 males and 4130 females who answered questions on physical activity and social status at 14 and 31 years of age in follow-up surveys of the Northern Finland birth cohort of 1966. Associations between explanatory factors and physical inactivity in adulthood were analyzed using multivariable logistic regression. RESULTS Infrequent participation in sports after school hours at 14 years of age and, in males, additionally a low grade in school sports, was associated with physical inactivity at the age of 31 years, independent of social circumstances in adulthood. Low social class of the childhood family was associated with physical inactivity in adolescence but not with inactivity at 31 years of age. Poor school achievement in adolescence was associated with adult inactivity independent of adolescent physical activity. CONCLUSION Infrequent participation in sports, a low grade in school sports, and poor school achievements in adolescence were associated with physical inactivity in adulthood. Participation in sports is to be strongly supported among all adolescents because of its long-term beneficial effects on adult health through its tendency to reduce the probability of adult inactivity.

Chronic Chlamydia pneumoniae Infection Is Associated With a Serum Lipid Profile Known to Be a Risk Factor for Atherosclerosis

Chlamydia pneumoniae infection has been associated with coronary heart disease. To evaluate the mechanisms of this association, we studied whether chronic C. pneumoniae infection affects serum lipid values similarly to acute infections. Triglyceride, total and HDL cholesterol concentrations, and C. pneumoniae antibodies were measured from paired serum samples of 415 Finnish males taken 3 years apart. Chronic infection, defined as persistent IgG and IgA antibodies, was found in 20%, and the antibodies were negative (IgG < 32 and IgA < 16 in both samples) in 15% of the cases studied. The serum triglyceride and total cholesterol concentrations were higher in the subjects with a chronic C. pneumoniae infection than in the subjects with no antibodies (1.23 versus 1.03 mmol/L and 6.41 versus 6.31 mmol/L, respectively). The HDL cholesterol concentrations and the ratios of HDL cholesterol to total cholesterol were significantly decreased in the subjects with chronic infection (1.24 versus 1.36 mmol/L, P = .026; and 0.19 versus 0.22, P = .018, respectively). Chronic C. pneumoniae infection seems to be associated with a serum lipid profile considered to increase the risk of atherosclerosis. This finding supports the hypothesis that infections play a role in the pathogenesis of atherosclerosis.

Prevalence of degenerative imaging findings in lumbar magnetic resonance imaging among young adults.

Study Design. A cross-sectional imaging study of young adults. Objective. To investigate the prevalence of disc degeneration (DD) and displacement, anular tears, and Modic changes in lumbar magnetic resonance imaging (MRI) among young adults. Summary of Background Data. Although low back pain in young adulthood is common, the prevalence of spinal MRI findings at this age remains virtually unknown. Methods. The study population was a subcohort of the Northern Finland Birth Cohort 1986. Subjects living within 100 km of Oulu (n = 874) were invited to participate in lumbar MRI at 20 to 22 years of age (mean: 21.2 years). Degree of DD, type of Modic changes, and presence of disc bulges, herniations, high intensity zone (HIZ) lesions, and radial tears at all lumbar levels were assessed. Results. Three hundred twenty-five women and 233 men (n = 558) attended the MR imaging. DD was significantly more frequent in men (54% vs. 42%, P = 0.005), as was multiple DD (21% vs. 14%, P = 0.036). The prevalences of disc bulges and radial tears were 25% and 9.1%, respectively, without gender differences. HIZ lesions were more common among women than men (8.6% vs. 4.3%, P = 0.046), whereas herniations were significantly more common among men (5.6% vs. 2.5%, P = 0.047). Only 2 disc extrusions were observed, one in each gender. All degenerative disc findings were more common at the L5–S1 level except HIZ lesions, which were most likely at L4–L5. The prevalence of the Modic changes was 1.4%, without gender difference, type I being more common than type II. Typically, Modic changes were located adjacent to a DD Grade 4 disc and at the 2 lowest levels. Conclusion. Almost half of young Finnish adult aged 21 years had at least one degenerated disc, and a quarter had a bulging disc. Modic changes and disc herniations were, however, relatively rare.

Changes in summer temperature and heat-related mortality since 1971 in North Carolina, South Finland, and Southeast England☆

Three climatically diverse regions were studied to determine the impact of temperature change on heat-related mortality from 1971 to 1997. Median regressions showed that May-August temperatures in North Carolina rose by 1.0 degrees C (95% CL 0.0-2.0 degrees C) from 23.5 degrees C (74.3 degrees F), were unchanged in South Finland at 13.5 degrees C (56.3 degrees F), and rose in Southeast England 2.1 degrees C (0.3-4.0 degrees C) from 14.9 degrees C (58.8 degrees F). After determining for each region the daily temperature (as a 3 degrees C band) at which the mortality was the lowest, annual heat-related mortality was obtained as excess mortality per million at temperatures above this. Annual heat-related mortality per million (among the population at risk, aged 55+) fell in North Carolina by 212 (59-365) from 228 (140-317) to only 16 (not significant, NS); fell in South Finland by 282 (66-500) from 382 (257-507) to 99 (NS); and fell in Southeast England by 2.4 (NS) from 111 (41-180) to 108 (41-176). The falls in North Carolina and South Finland remained significant after allowances were made for changes in age, sex, and baseline mortality. Increased air conditioning probably explains the virtual disappearance of heat-related mortality in the hottest region, North Carolina, despite warmer summers. Other lifestyle changes associated with increasing prosperity probably explain the favorable trends in the cooler regions.

Does Lumbar Disc Degeneration on Magnetic Resonance Imaging Associate With Low Back Symptom Severity in Young Finnish Adults

Study Design. A cross-sectional magnetic resonance imaging study with questionnaires on low back pain (LBP) and functional limitations. Objective. To investigate the association between lumbar intervertebral disc degeneration (DD) and low back symptom severity among young Finnish adults. Summary of Background Data. Both LBP and lumbar DD are common already in adolescence, but very little is known of their association in young adults. Methods. Young adults belonging to a birth cohort (n=874) were invited to lumbar magnetic resonance imaging using a 1.5-T scanner. Data on LBP and functional limitations at the ages of 18, 19, and 21 years were used to cluster the subjects with respect to low back symptoms using latent class analysis. The prevalence and 95% confidence intervals of DD at 21 years and the sum score of DD at all lumbar levels were compared between the clusters. The contribution of DD and other imaging findings (herniations, anular tears, Modic changes, spondylolytic defects) to symptom severity was analyzed with logistic regression analysis. Results. Latent class analysis produced five clusters from the 554 subjects, ranging from a cluster where subjects (n=65) had been painful at all time points to an asymptomatic cluster (n=168). DD was more prevalent in the three most symptomatic clusters compared to the two least symptomatic ones. Similar findings were obtained for the DD sum scores. Lumbar DD was related to symptom severity independently of other degenerative findings. Moreover, moderately degenerated discs were more likely than mildly degenerated discs to be associated with the most severe low back symptoms. Conclusion. Intervertebral DD was associated with low back symptom severity among young adults, suggesting that the symptoms may have a discogenic origin at this age. However, DD was also found in one-third of asymptomatic subjects.

Change in the level of physical activity from adolescence into adulthood and obesity at the age of 31 years

OBJECTIVE: To evaluate how a change in the level of leisure-time physical activity from adolescence into adulthood is associated with overall and abdominal obesity at the age of 31 y.DESIGN: Prospective follow-up study of Northern Finland birth cohort of 1966.SUBJECTS: In all, a population of 2834 males and 2872 females aged 31 y was studied.MEASUREMENTS: At the age of 31 y, overweight was defined as a body mass index (BMI) of 25.0–29.9 kg/m2 and obesity as a BMI of 30.0 kg/m2 or more. The cutoff points of waist circumference for mild and severe abdominal obesity were 94.0 and 102.0 cm in males and 80.0 and 88.0 cm in females. The change in the level of physical activity (at least moderately active vs inactive) was evaluated by inquiries conducted at the ages of 14 and 31 y. The odds ratios (OR) and their 95% confidence intervals (CI) obtained from logistic regression were adjusted for maternal BMI before pregnancy, BMI at the age of 14 y, alcohol intake, occupational physical activity, smoking, and, in the case of females, for parity at age 31 y.RESULTS: Becoming inactive during the transition from adolescence to adulthood was associated with overall overweight in males (OR 1.49, CI 1.18–1.89), overall obesity in males (OR 1.53, CI 0.99–2.37) and females (OR 1.51, CI 0.94–2.44), and with severe abdominal obesity in females (OR 1.80, CI 1.13–2.86). Being persistently inactive from adolescence to adulthood was associated with mild abdominal obesity in males (OR 1.83, CI 1.13–2.95), but not with other obesity measures in either gender after adjustment for confounding factors.CONCLUSIONS: Becoming inactive during the transition from adolescence to adulthood is related to overall obesity in both genders, and to severe abdominal obesity in females at the age of 31 y. The results emphasize the role of continued physical activity from adolescence into adulthood in the prevention of adult obesity.

Environmental temperature and mortality

Abstract In Finland, mortality increases steeply in autumn, reaches a peak during the Christhmas holidays and declines slowly towards a trough in August. The relative excess in daily mortality (peak vs. trough) is 30% for coronary heart disease, 40% for cerebral vascular accidents and 90% for diseases of the respiratory organs. There is a secondary peak in Midsummer, especially in coronary deaths of working aged men. Mortality is lowest at mean daily temperature of +14°C, and it increases slowly with falling temperature and steeply with increasing temperature. An estimated 2000–3000 extra deaths occur in Finland during the cold season, most of which are people aged 65 years and over but 20% at working age. The number of people dying from high temperatures (over +14°C) in this country in a normal year is 100-200. Heat deaths are mostly certified as being due to cardiovascular or respiratory conditions. Exposure to cold air causes a rise in blood pressure and haemoconcentration which lead to increased tendency to vascular thromboses. In hot weather, haemoconcentration due to sweating and perspiration increases blood viscosity and the risk of thrombosis. Both cold and heat are significant public health hazards which should be taken into account in health care and education of health professionals. (Int J Circumpolar Health 2005; 64(5):451-458)

High serum alpha‐tocopherol, albumin, selenium and cholesterol, and low mortality from coronary heart disease in northern Finland

Abstract. Objectives. The mortality from coronary heart disease (CHD) is exceptionally low in northernmost Finland, the Sámi (formerly known as Lapp) area. To clarify the reasons for this, the levels of serum cholesterol, other classic risk factors, and major antioxidants, alpha‐tocopherol, retinol, albumin and selenium were determined in males living in the low‐mortality area and in a reference area.

Cold and the risk of cardiovascular diseases. A review.

The higher occurrence of cardiovascular diseases in winter is well known, and several explanatory mechanisms have been suggested based on increased blood pressure, haematological changes and respiratory infections. Most investigations have used ecological data such as daily temperatures recorded at weather stations and mortality in the general population. Cause-specific mortality is the outcome measure most commonly used. Local myocardial infarction community registers would offer an ideal database, but may suffer from inadequate statistical power. Hospital discharge records, linked with out-of-hospital deaths, provide a powerful tool for detecting even weak effects of temperature. The association of coronary heart disease and temperature is usually U-shaped, mortality being lowest within the range 15–20 degrees C and higher on both sides of this. The increase in mortality on the colder side is in the region of 1% per 1 degree C fall in temperature, but the increase on the warmer side may be very steep. The exact location of the minimum temperature and the magnitude of the effect can vary between countries. In Finland the winter excess mortality from coronary heart disease has been levelling off during recent decades, but it still represents approximately 6% of annual deaths due to this condition.