Prevalence of cold-related musculoskeletal pain according to self-reported threshold temperature among the Finnish adult population.

BACKGROUND: Exposure to cold reportedly increases musculoskeletal pains. We assessed the prevalence of such pain and self-reported threshold temperature (TT) at which the pain emerges. METHODS: A random sample of 6591 people in Finland, aged 25-74 years, answered a questionnaire on repeated cold-related musculoskeletal pain (CMP) and its TT. The response rate was 64%. We used quantile regression to quantify the effects of personal characteristics and region of residence on TT at various locations of its distribution. RESULTS: Of the participants, 1892 (30%) experienced CMP in at least one body site and 1692 reported TT. Ten percent of the participants who perceived CMP did so at -2 °C, 50% at -14 °C and 90% at -23 °C. Residence in the South elevated TT by 1-6 °C compared with residence in the North, depending on the proportion of participants reporting CMP at various temperatures. Joint disorders increased TT at milder temperatures, at which only 10% of all participants perceived CMP, whereas back disorders did so mainly at lower temperatures, at which 70% were affected. Overweight was associated with a 2 °C lower TT, and physical inactivity with a 1 °C higher TT, and TT increased by 1 °C per 10-year increase in age. The greatest model-estimated difference in median TT between subgroups was 12 °C. CONCLUSIONS: People suffering from musculoskeletal disorders and those living in the warmer areas of Finland need special advice to protect themselves against the cold. Our study provides preliminary information to support such advice.

Intra-articular corticoid injection induces circulating glucocorticoid bioactivity and systemic immune activation in juvenile idiopathic arthritis.

OBJECTIVE: To study the systemic effects of intra-articular (IA) glucocorticoid (GC) injections in juvenile idiopathic arthritis (JIA). METHODS: The study group comprised 21 JIA patients being treated with IA methylprednisolone [MP (n = 15) or MP plus triamcinolone hexacetonide (THA) (n = 6)] prescribed on clinical indications. The systemic effect of MP was assessed by measuring circulating glucocorticoid bioactivity (GBA) with a recombinant cell transactivation assay 7 and 24 h after the IA injections, and after 2 months. The systemic immunological responses were studied with a novel assay for testing patient serum-induced changes in the secretion of interferon (IFN)-γ and interleukin (IL)-5 from target cells. RESULTS: Administration of IA GC induced serum GBA (p = 0.001) and suppressed circulating cortisol levels (p = 0.002) 7 h after the injection. Serum withdrawn 24 h after the IA injection induced less IL-5 secretion from mitogen-activated target cells when compared with pre-treatment sera (p = 0.036). This decrease in target cell T helper (Th)2 response (IL-5) was MP dose related (r = -0.550, p = 0.018). High IL-5 secretion from target cells prior to the IA injections was associated with good clinical outcome at 2 months, seen as a low number of active (p = 0.044) and restricted joints (p = 0.049). CONCLUSION: IA GC injections have systemic effects that are reflected in the serum as an immediate elevation of GBA, a decrease of endogenous cortisol as well as a suppressive effect of patient serum on target cell IL-5 secretion. These systemic effects may play a role in the attenuation of disease activity.

Temperature limit values for touching cold surfaces with the fingertip.

OBJECTIVES: At the request of the European Commission and in the framework of the European Machinery Directive, research was performed in five different laboratories to develop specifications for surface temperature limit values for the short-term accidental touching of the fingertip with cold surfaces. METHODS: Data were collected in four laboratories with a total of 20 males and 20 females performing a grand total of 1655 exposures. Each touched polished blocks of aluminium, stainless steel, nylon-6 and wood using the distal phalanx of the index finger with a contact force of 1.0, 2.9 and 9.8 N, at surface temperatures from +2 to -40 degrees C for a maximum duration of 120 s. Conditions were selected in order to elicit varying rates of skin cooling upon contact. Contact temperature (TC) of the fingertip was measured over time using a T-type thermocouple. RESULTS: A database obtained from the experiments was collated and analysed to characterize fingertip contact cooling across a range of materials and surface temperatures. The database was subsequently used to develop a predictive model to describe the contact duration required for skin contact temperature to reach the physiological criteria of onset of pain (15 degrees C), onset of numbness (7 degrees C) and onset of frostbite risk (0 degrees C). CONCLUSIONS: The data reflect the strong link between the risk of skin damage and the thermal properties of the material touched. For aluminium and steel, skin temperatures of 0 degrees C occurs within 2-6 s at surface temperatures of -15 degrees C. For non-metallic surfaces, onset of numbness occurs within 15-65 s of contact at -35 degrees C and onset of cold pain occurs within 5 s of contact at -20 degrees C. The predictive model subsequently developed was a non-linear exponential expression also reflecting the effects of material thermal properties and initial temperature. This model provides information for the protection of workers against the risk of cold injury by establishing the temperature limits of cold touchable surfaces for a broad range of materials, and it is now proposed as guidance values in a new international standard.

Oral health in women with pregnancy and delivery complications.

Oral health was retrospectively studied in 207 women (mean age 30 years) in the Helsinki Womens' Hospital with the hypothesis that women with pregnancy complications and/or delivery complications would present poorer dental status than women without complications. Computerized dental records of the City of Helsinki Health Department were used with decayed, missing, filled index (DMF) and community periodontal index (CPI) scoring systems and a summary dental health index (DHI) was constructed for statistics. In 72%, the delivery was uncomplicated, while 18% had Caesarean section. Of the women, 8% had gestational diabetes, 7.1% had gestational hypertension, and 1.8% had preeclampsia. Fifteen (6.6%) preterm babies were born; eight (3.5%) babies weighed <2.500 g, seven (3.2%) received a 1-min Apgar point <7 indicating less than satisfactory state of the newborn. DMF was 12.9+/-6.6 in women without complications compared to 15.3+/-6.7 in women with complications (n.s.). CPI values did not differ between the groups. The mean DHI values were 2.07 in women with normal pregnancy complications and no delivery complications, 2.23 in those with pregnancy complications, and 2.13 in those with delivery complications, respectively. In logistic regression analysis, no oral health parameters associated with any complications. Thus, this study failed to show an association between poor dental health and pregnancy or delivery complications.

Cardiorespiratory fitness of males and females of northern Finland birth cohort of 1966 at age 31.

This study aimed to measure cardiorespiratory fitness of about 9000 males and females at age 31, to produce the reference values and relate them to the level of physical activity and body mass index (BMI). Study population was the Northern Finland birth cohort of 1966. At age 31, 8786 persons responded to a postal inquiry including questions about physical activity and 5497 of them also performed a step test. A sample of 123 persons performed a maximal exercise test with direct measurement of peak oxygen uptake (VO(2peak)). This was done to develop VO(2peak) prediction models on the basis of heart rate after a step test, BMI and frequency of brisk physical activity. These models were used to calculate VO(2peak) for the whole study population. Mean VO(2peak) +/- standard deviation was 43.0 +/- 4.6 ml.kg(-1).min(-1) in 4071 males and 34.3 +/- 4.3 ml.kg(-1).min(-1) in 4367 females. A graded dose-response relationship was observed in males and females between the frequency of participation in brisk exercise and VO(2peak). Similar dose-response relationship was also observed in overweight and obese persons, although the level of VO(2peak) was lower in persons with increased BMI. At age 31, very low levels of VO(2peak) seemed to be associated with a combination of infrequent participation in brisk exercise and increased BMI. These reference values can be used in the interpretation of fitness test results and in physical activity counselling.

Simulated parachute descent in the cold: thermal responses and manual performance.

BACKGROUND: Ejection from a fighter aircraft can expose the pilot to extreme cold and windy conditions. Knowledge of the effects of such conditions on thermal responses and performance of the pilot is scarce. HYPOTHESIS: It is expected that the temperature of bare skin and fingers may decrease to the level where health and/or performance are hampered. METHODS: Seven fighter pilots performed a simulated parachute descent (SPD) at ambient temperature (Ta) of -35 degrees C and wind velocity of 10 m x s(-1). The 8-min SPD was followed by a 60-min cold exposure (CE) at Ta of -20 degrees C. Flight garments with or without immersion suit were used. During SPD the subjects performed basic survival tasks. Rectal and skin temperatures were measured and manual performance was tested. RESULTS: Thermal responses did not significantly differ between the clothing ensembles. Mean skin temperature was 28 degrees C and 27 degrees C at the end of SPD and CE, respectively. The cheek temperature was 9 degrees C (range 3.2-13.8 degrees C) at the end of SPD. Finger skin temperature was 7 degrees C and 9 degrees C at the end of SPD and CE, respectively. The subjects could perform the defined tasks during SPD while manual performance was slightly impaired during CE. CONCLUSIONS: Subjects could tolerate the 8-min SPD and the following CE in the studied conditions without a loss of vital performance in basic survival actions. However, the risk of frostbite on the uncovered skin area as well as numbness of the fingers may jeopardize pilots' health and performance during parachuting.

Temperature limit values for gripping cold surfaces.

OBJECTIVES: At the request of the European Commission and in the framework of the European Machinery Directive, research was conducted jointly in five different laboratories to develop specifications for surface temperature limit values for the gripping and handling of cold items. METHODS: Four hundred and fourteen experiments were run where male and female subjects were invited to grip for up to 20 min cold bars of different contact coefficients, i.e. polished wood, nylon, stone, steel and aluminium. The air temperature and the bars' initial surface temperatures ranged between 0 and -30 degrees C for the various experiments. While gripping the bars, either only the hand or the whole body was exposed to cold. RESULTS: The data were used to develop a prediction formula and a graph of the surface temperature limit values in order for the skin contact temperature not to reach <15 degrees C. This duration is shown to offer a significant degree of safety with respect to the minimal surface temperature spontaneously tolerated by the subjects. CONCLUSIONS: Experiments and modelling must be pursued to extend these data to other conditions of exposure.

Effect of regular winter swimming on the activity of the sympathoadrenal system before and after a single cold water immersion.

This study deals with the adaptation of the sympathoadrenal responses to an acute cold water immersion in ordinary winter swimmers. Hormonal responses were determined at the beginning of the winter swimming period in the autumn and after regular swimming for one and three months. Water temperature in the river was 10 degrees C at the beginning and 4 degrees C after one and three months. The mean duration of the test immersion was 36 s. Plasma catecholamine levels determined before the test immersion decreased with the winter swimming period for one month (NA, p < 0.001, A, p < 0.01). The test immersion significantly increased noradrenaline levels (p < 0.001). Plasma adrenaline and serum cortisol levels were increased or decreased by the immersion. After 1 month's swimming the test immersion to 4 degrees C increased noradrenaline to a similar level than the immersion to 10 degrees C at the beginning. Regularly practiced winter swimming for three months led to diminished catecholamine levels measured immediately after the test immersion (p < 0.01). The results suggest that cold adaptation induced by winter swimming attenuates the catecholamine responses to cold water. Adrenaline responses are also affected by its level prior to the immersion.

Blood pressure and endocrine responses of healthy subjects in cold pressor test after acutely increased dietary sodium intake.

The objective of the study was to compare blood pressure and endocrine responses in a cold pressure test in young healthy subjects who had shown increased blood pressure during an acutely increased sodium intake. Subjects (n = 53) added 121 mmol sodium into their normal diet for one week. If the mean arterial pressure had increased by a minimum of 5 mmHg compared to the control measure, they were selected for the experiments. The selected subjects (n = 8) were given 121 mmol supplemental sodium d-1 for 14 days after which they immersed the right hand into a cold (+10 degrees C) water bath for 5 min. The blood pressure increased (P < 0.05) during the test and was independent of the sodium intake. The plasma noradrenaline increased from 2.41 +/- 0.38 nmol l-1 to 2.82 +/- 0.42 nmol l-1 (P < 0.05) with normal diet and from 1.85 +/- 0.29 nmol l-1 to 2.40 +/- 0.37 nmol l-1 (P < 0.05) with high sodium diet. The starting concentrations and the endpoint concentrations were statistically similar. The plasma levels of natriuretic peptides (NT-proANP, ANP and BNP) did not change during the test, and the concentrations were independent of the sodium diet. To conclude, acutely increased sodium intake does not change blood pressure or hormonal responses in a cold pressor test in young healthy subjects.

Are the blood pressure and endocrine responses of healthy subjects exposed to cold stress altered by an acutely increased sodium intake?

In the study reported here, we examined blood pressure and endocrine responses in cold conditions during salt load in young healthy subjects who had previously shown increased resting blood pressure during acutely increased sodium intake. Subjects (n = 53) added 121 mmol sodium into their normal diet for 1 week. If their mean arterial pressure had increased by a minimum of 5 mmHg compared to the previous measure they were selected for subsequent experiments. The subjects (n = 8) were given 121 mmol supplemental sodium.day-1 for 14 days. They were then put into a wind tunnel for 15 min (temperature--15 degrees C, wind speed 3.5.ms-1). Their blood pressure increased (P < 0.05) during the cold exposure, independent of the sodium intake. Their mean (SEM) plasma noradrenaline increased from 3.58 (0.62) nmol.l-1 to 5.61 (0.79) nmol.l-1 (P < 0.05) when the subjects were given a normal diet, and from 2.45 (0.57) nmol.l-1 to 5.06 (0.56) nmol.l-1 (P < 0.05) when the subjects were given an elevated sodium diet. The starting concentrations and the endpoint concentrations were statistically similar. The plasma levels of the N-terminal fragment of pro-atrial natriuretic peptide decreased during the whole-body cold exposure: with the sodium load the change was from 256.6 (25.5) nmol.l-1 to 208.0 (25.3) nmol.l-1, and with the normal diet, from 205.8 (16.4) nmol.l-1 to 175.1 (16.1) nmol.l-1. The haematocrit and red blood cell count increased (P < 0.05) with normal and elevated sodium diet in cold conditions, but haemoglobin increased (P < 0.05) only with high salt in cold conditions. To conclude, acutely increased sodium intake does not change the blood pressure response or hormonal responses to exposure to acute cold stress in healthy subjects.

Outdoor clothing: its relationship to geography, climate, behaviour and cold-related mortality in Europe.

It has been suggested, that the inhabitants of northern European regions, who experience little cold-related mortality, protect themselves outdoors by wearing more clothing, at the same temperature, than people living in southern regions where such mortality is high. Outdoor clothing data were collected in eight regions from 6583 people divided by sex and age group (50-59 and 65-74 years). Across Europe, the total clothing worn (as assessed by dry thermal insulation and numbers of items or layers) increased significantly with cold, wind, less physical activity and longer periods outdoors. Men wore 0.14 clo (1 clo = 0.115 m2 K W-1) more than women and the older people wore 0.05 clo more than the younger group (both P < 0.001). After allowance for these factors, regional differences in insulation and item number were correlated (r = -0.74, P = 0.037; r = -0.74, P = 0.036 respectively), but not those in clothing layers (r = -0.21; P = 0.61), with indices of cold-related mortality. Cold weather most increased the wearing of gloves, scarves and hats. The geographical variation in the wearing of these three together items more closely matched that in cold-related mortality (r = -0.89, P = 0.003). A possible explanation for this may be that they protect the head and hands, where stimulation by cold greatly increases peripheral vasoconstriction causing a rise in blood pressure that procedure haemoconcentration and raised cardiovascular risk.

Effects of whole body cooling on sensory perception and manual performance in subjects with Raynaud's phenomenon.

Patients with Raynaud's phenomenon (RP) have abnormal digital vasoconstriction in response to cold. The aim of the study was to investigate the effects of cooling on sensory perception and manual performance in healthy male subjects and subjects with RP. There were two groups of subjects with primary RP: 12 subjects fulfilled the criteria of Lewis (L) and the other 12 the more critical criteria of Maricq (M). Control group (C) consisted of 19 healthy men. Subjects were exposed to 5 degrees C for 60 min. Skin temperatures were measured. Finger dexterity, pinch strength, abduction/adduction of fingers, pressure perception threshold and vibration perception threshold were tested during the exposure every 15 min. At the beginning of the exposure the mean (S.E.) finger temperature was 2.5 (1.2) degrees C (P<0.05) lower in M than in C. Manual performance and sensory perception were impaired due to the cooling, the impairment being significantly greater in M than in C. Responses of L were between those of M and C. In a given finger temperature vibration and pressure sensibility and manual performance were lower in M and L than in C. In conclusion, cold exposure decreased sensory perception and manual performance in the subjects with RP to a lower level than in the healthy subjects. Non-thermal factors may also decrease performance in RP.

Effects of metabolic rate on thermal responses at different air velocities in -10 degrees C.

The effects of exercise intensity on thermoregulatory responses in cold (-10 degrees C) in a 0.2 (still air, NoWi), 1.0 (Wi1), and 5.0 (Wi5) m x s(-1) wind were studied. Eight young and healthy men, preconditioned in thermoneutral (+20 degrees C) environment for 60 min, walked for 60 min on the treadmill at 2.8 km/h with different combinations of wind and exercise intensity. Exercise level was adjusted by changing the inclination of the treadmill between 0 degrees (lower exercise intensity, metabolic rate 124 W x m(-2), LE) and 6 degrees (higher exercise intensity, metabolic rate 195 W x m(-2), HE). Due to exercise increased heat production and circulatory adjustments, the rectal temperature (T(re)), mean skin temperature (Tsk) and mean body temperature (Tb) were significantly higher at the end of HE in comparison to LE in NoWi and Wi1, and T(re) and Tb also in Wi5. Tsk and Tb were significantly decreased by 5.0 m x s(-1) wind in comparison to NoWi and Wi1. The higher exercise intensity was intense enough to diminish peripheral vasoconstriction and consequently the finger skin temperature was significantly higher at the end of HE in comparison to LE in NoWi and Wi1. Mean heat flux from the skin was unaffected by the exercise intensity. At LE oxygen consumption (VO2) was significantly higher in Wi5 than NoWi and Wi1. Heart rate was unaffected by the wind speed. The results suggest that, with studied exercise intensities, produced without changes in walking speed, the metabolic rate is not so important that it should be taken into consideration in the calculation of wind chill index.

Poor dental status increases acetaldehyde production from ethanol in saliva: a possible link to increased oral cancer risk among heavy drinkers.

Epidemiological data support evidence that poor dental status increases oral cavity cancer risk especially among heavy alcohol consumers, but the causality of this finding is unclear. The enzymatic conversion of ethanol by the physiological oral microflora may lead to an accumulation of the highly carcinogenic intermediate acetaldehyde. This study was conducted to evaluate the role of dental status on the microbial production of acetaldehyde from ethanol in saliva. The microbial acetaldehyde production from ethanol was related to the dental score in 132 volunteers. After adjustment for smoking, alcohol consumption, age and gender, poor dental status was shown to lead to an approximately twofold increase in salivary acetaldehyde production from ethanol (P=0.02). Our results could be an important factor underlying the role of poor dental hygiene and status in oral cancer risk associated with ethanol drinking.

Serum concentrations of collagen degrading enzymes and their inhibitors after downhill running.

In the present study the release of proteins degrading extracellular matrix compounds to circulation was measured after damaging exercise in humans. Muscle damage was induced by downhill running; furthermore, the exercise was performed at both cold temperature (5 degrees C) and room temperature (22 degrees C) to study also the possible effect of environmental temperature on serum concentrations of matrix metalloproteinases MMP-2 and MMP-9, tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2, and MMP-2/TIMP-2 complex, and muscle damage monitored by serum creatine kinase measurements. Results were compared with those obtained from patients having rhabdomyolysis, myositis and Becker muscular dystrophy. The present study demonstrates an acute increase in serum concentrations of MMP-9, TIMP-1, and MMP-2/TIMP-2 complex, but no changes in serum MMP-2 concentrations in response to eccentric exercise. Serum creatine kinase activity data suggest greater muscle damage after downhill running in a cold environment than at room temperature. The present observations about at most slight changes in serum MMP and TIMP concentrations and lack of their correlation to increased serum creatine kinase after exercise indicate that serum measurements of MMPs and TIMPs do not sensitively respond to exercise induced skeletal muscle damage and extracellular matrix regeneration. On the other hand, severe skeletal muscle damage, such as rhabdomyolysis, myositis and Becker muscular dystrophy, seemed to have an effect on serum MMP and TIMP concentrations.

Predisposing factors and prevention of frostbite.

This review focuses on the physiological, behavioural and environmental factors which predispose to frostbite. Also prevention of frostbite is summarised. Predisposing factors may increase heat loss, decrease heat production, decrease the insulation of the clothing, make people especially susceptible to cold or make them to behave inadequately. Marked increase in convective or conductive heat loss is often the immediate reason for frostbite. Wind (as described by wind chill index) increases convective heat loss and touching of metal objects increases conductive cooling. Poor insulation of the clothing is also a common reason of frostbite. The insulation can be insufficient when clothing is wet, tight, permeable to wind or does not cover the cold sensitive body parts. Individual factors predisposing to frostbite are inadequate behaviour, low physical fitness, fatigue, dehydration, earlier cold injuries, sickness or poor circulation in peripheral parts of the body. Frostbite is often associated with the use of alcohol. To prevent frostbite, it is necessary to recognise cold risks, practise tasks in the cold, eat and drink well, have physical exercise, have sufficient clothing (also spare clothing), change into dry clothing if necessary and take care of companions. In the cold it is not advisable to get fatigued until exhaustion, sweat excessively, use tight and/or wet clothing, drink alcohol, smoke and expose oneself unnecessarily to wind, metals or fluids.

Sequelae of moderate finger frostbite as assessed by subjective sensations, clinical signs, and thermophysiological responses.

The aim of the study was to investigate prevalence and qualities of sequelae following moderate finger frostbite. The study material comprised 30 subjects, who had suffered second-degree frostbite (73% contact frostbite) 4-11 years before this study. In clinical tests 66% of the subjects had an elevated tendency for vasospasm, yet only 20% suffered from white fingers. However, no marked traces of frostbite-related alterations were observed in systemic cardiovascular reflex tests or in X-ray examinations of the frostbite area. Subjective assessments revealed a high prevalence of sequelae (63%), although the primary frostbite was moderate and local. The sequelae in the frostbite area included hypersensitivity to cold (53%), numbness of fingers (40%), and declined sensitivity of touch (33%). Also working ability was lowered due to frostbite sequelae (13%). In cold air provocation tests, the skin temperature of the frostbitten areas decreased more quickly and reached lower values than in healthy control subjects. In conclusion the suffered frostbite was associated with an increased tendency for vasospasm. Subjective sensations of the frostbitten area were associated with thermophysiological changes. The sequelae were reported to worsen in the cold environment thus emphasizing the probable occupational limitations of even moderate cold injury.