Prevalence of cold-related complaints, symptoms and injuries in the general population: the FINRISK 2002 cold substudy.

The prevalence of cold-related complaints and symptoms in the general population has remained unknown. As part of the nationwide FINRISK 2002 health survey performed in Finland, 8,723 people aged 25-64 years filled in a questionnaire asking about the number of hours spent weekly in cold air, their sensations during cold exposure, cold-related complaints, symptoms of diseases, and degradation of performance. Cold thermal sensations at +5 degrees C to -5 degrees C were reported by 35% of men and 46% of women. Almost all subjects reported at least some cold-related complaints, most commonly musculoskeletal pain (men 30%, women 27%), followed by respiratory (25% / 29%), white finger (15% / 18%) and episodic peripheral circulation symptoms (12% / 15%). Decreased mental or physical performance in cold was reported by 75% of men and 70% of women, most commonly impairing manual dexterity and tactile sense. With declining temperature, the first symptom to emerge was pain in the elbow or the forearm (at -3 degrees C), followed by increased excretion of mucus from the lungs (-5 degrees C), while most other symptoms appeared only at lower temperatures of -15 degrees C to -20 degrees C. Most symptoms showed little or no association with the weekly duration of exposure, with the exception of cold-induced pain at most sites. Although, in general, Finns are well adapted to the cold climate, the high prevalence of cold-related complaints poses a challenge to the health care system in terms of decreased performance and the possibility that such symptoms predict more serious health effects, such as increased mortality.

Factors affecting outdoor exposure in winter: population-based study.

The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study (n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

Impacts of cold climate on human heat balance, performance and health in circumpolar areas.

In circumpolar areas the climate remains cool or thermoneutral during the majority of the days of the year spite of global warming. Therefore, health consequences related to cold exposure represent also in the future the majority of climate-related adverse health effects. Hot summers may be an exception. At ambient temperatures below +10 - +12 degrees C, humans experience cold stress of varying degree. Man can compensate a 10 degrees C change in ambient temperature by changing metabolic heat production by 30-40 W m(-2) or by wearing an additional/taking off ca. 0.4 clo units (corresponding to one thick clothing layer). Cold ambient temperature may be a risk for human health and cause varying levels of performance limitations. The impacts of cold exposure on health and wellbeing cause a burden to many societies in terms of lowered productivity and higher costs related to health care systems as well as public health planning and management. In order to provide preventive and protective public health actions for cold-induced adverse health effects, it is important to recognize cold related injuries, illnesses and symptoms and their turn-up temperatures, and to identify the most at-risk population subgroups and factors that increase or decrease the health risks posed by cold ambient temperatures. The majority of cold-related harmful health impacts can be prevented or managed by correct preventive and protective actions. Rapid unpredictable changes are more difficult to compensate because of lack of experience (affecting attitude and skills), preparedness (vehicles, garments, supplies, logistics etc.) and/or acclimatization.

Not all maps are equal: GIS and spatial analysis in epidemiology.

Recently, Geographical Information System (GIS) has emerged as an innovative and important component of many projects in public health and epidemiology. One of the most useful functions of GIS in epidemiology continues to be its utility in basic mapping. GIS may also involve more sophisticated spatial analysis of disease occurrence and contributing environmental factors. Depending on the quantity and quality of data and the methodology used in analysis, a given map may be either useful or misleading. Although visual analyses (mapped evidence) strengthened by exploratory analyses are mostly sufficient for epidemiologists, the formal testing of certain hypotheses or the estimation of relationships between measures of disease incidence and, for example, environmental covariates require quantitative modelling of disease distribution. It is a promising prospect that spatial statistics and GIS technology have slowly started to merge. However, whether GIS will be useful in the model-based approach and the prediction in, for example, epidemiology remains to be seen. The desired future development of GIS requires a switch of emphasis from data and information to knowledge.