Köldexponering och hälsa : En studie av neurologiska och vaskulära handsymptom i norra Sverige

Background: Living in a cold climate is associated with several adverse health effects. The main purpose of this thesis was to describe cold exposure characteristics in northern Sweden, and investigate the associations between such exposure and the reporting of neurological and vascular hand symptoms. One common cold-related hand symptom is Raynaud’s phenomenon, defined as episodic attacks of acral pallor or cyanosis. There is evidence to suggest that cold exposure can act both as a causal factor and a trigger for such vasospastic symptoms. Other important associated factors include exposure to hand-arm vibration and the presence of rheumatic disease. A somewhat similar clinical entity, cold sensitivity, is defined as a collection of acquired symptoms, resulting in an abnormal aversion to cold, with pain, sensory alterations, stiffness, or color changes, which may occur after a traumatic injury. The condition is hypothesized to mainly originate from nerve injury. The effects of cold exposure on hand function, the occurrence of cold sensitivity in the general population, the link between cold exposure and cold sensitivity, as well as the interface between cold sensitivity and Raynaud’s phenomenon are not fully understood. Therefore, this thesis was also intended to expand the knowledge on Raynaud’s phenomenon and cold sensitivity. Methods: Postal surveys were sent to a sample of men and women between 18 and 70 years of age, living in Norrbotten, Västerbotten, Västernorrland, and Jämtland, drawn from the national Swedish population register. The first survey collected data on 12,627 subjects, and the results were used to describe cold exposure characteristics, and broadly investigate the statistical associations with different neurological and vascular hand symptoms (Paper I). A follow-up survey was sent to a subset of responders, to form nested case–control studies on cold sensitivity (N=1,230; Paper II) and Raynaud’s phenomenon (N=1,400; Paper III). Subjects with cold sensitivity (N=12) from Paper II were subsequently recruited to a laboratory study, to investigate the vascular and neurosensory function of the hands, by means of physical examination, laser speckle contrast analysis before and after cold stress testing, and thermal quantitative sensory testing (Paper IV). Finally, healthy controls (N=1,239) from the case–control studies were used as a reference population for the Cold intolerance symptom severity questionnaire, to establish a cut-off for abnormal cold sensitivity (Paper V). Results: In Paper I, cold exposure was commonly reported, both during work and leisure time. Exposure was most pronounced in alpine regions, generally higher among men than women, and decreased with age. Highly cold-exposed occupational groups were militaries; agricultural, forestry and fishery workers; and crafts and related trades workers (e.g. construction workers). The correlation between occupational and leisure-time cold climate exposure was low. Men reported more occupational exposure to hand-arm vibration than women, but the correlation between occupational cold and vibration exposure was low. A range of neurological and vascular hand symptoms were statistically associated with high cold exposure, such as decreased perception to touch, warmth, and cold, as well as Raynaud’s phenomenon. In Paper II, cold sensitivity was significantly associated with previous frostbite affecting the hands, rheumatic disease, upper extremity nerve injury, migraine, vascular disease, and high body mass index (inversely), in a multiple conditional logistic regression model. In Paper III, Raynaud’s phenomenon was significantly associated with previous frostbite affecting the hands, first degree heredity, and high body mass index (inversely), in a similar model. Previous upper extremity nerve injury was suggested as a separating trait between Raynaud’s phenomenon and cold sensitivity. In Paper IV, laser speckle contrast analysis indicated disturbances in microvascular regulation, while physical examination and thermal quantitative sensory testing mainly yielded normal results. In Paper V, the 95th percentile for the Cold intolerance symptom severity score was 49.5 for men, and 53.0 for women. Conclusions: Cold exposure in the working-age population of northern Sweden varied with age, gender, occupation, and place of residence. Cold exposure was related to the reporting of neurological and vascular hand symptoms in the population as a whole. There was a major overlap between reporting cold sensitivity and Raynaud’s phenomenon, and the conditions shared several associated factors. Previous upper extremity nerve injury was suggested to be a separating trait, supporting the neurosensory pathophysiological hypothesis for cold sensitivity. Cold sensitivity was not effectively assessed by physical examination or thermal quantitative sensory testing. However, laser speckle contrast analysis could prove a useful tool in further studies on cold sensitivity. A Cold intolerance symptom severity score above 50 could be considered to indicate abnormal cold sensitivity, and be used to guide further care

Colloidal silver ingestion and severe anemia : a case report

Introduction: Colloidal silver ingestion as an alternative medicine treatment is becoming more common. This case report describes a patient with potential silver poisoning and severe anemia. Case description: A woman in her late sixties was transported to the emergency department because of progressive fatigue and nausea. She had been drinking 150 µg of colloidal silver daily for two to three weeks. Blood sampling revealed severe anemia (red blood cell count 48 g/L) and a whole-blood silver concentration of 20 µg/L. Liver function tests were abnormal and there were signs of incipient heart failure with increased pro-brain natriuretic peptide, troponin T, as well as pleural effusion. She was stabilized with blood transfusion and symptomatic treatment, to be discharged from the hospital after ten days. The patient improved over the following six weeks and the whole-blood silver concentration decreased to 3.3 µg/L after about three months. Conclusions: The case demonstrates the potential effects of silver intake on the hematopoietic, hepatic, and cardiovascular systems. This highlights the possible risks associated with emerging alternative medicine therapies

Köldexponering och hälsa : En studie av neurologiska och vaskulära handsymptom i norra Sverige

Background: Living in a cold climate is associated with several adverse health effects. The main purpose of this thesis was to describe cold exposure characteristics in northern Sweden, and investigate the associations between such exposure and the reporting of neurological and vascular hand symptoms. One common cold-related hand symptom is Raynaud’s phenomenon, defined as episodic attacks of acral pallor or cyanosis. There is evidence to suggest that cold exposure can act both as a causal factor and a trigger for such vasospastic symptoms. Other important associated factors include exposure to hand-arm vibration and the presence of rheumatic disease. A somewhat similar clinical entity, cold sensitivity, is defined as a collection of acquired symptoms, resulting in an abnormal aversion to cold, with pain, sensory alterations, stiffness, or color changes, which may occur after a traumatic injury. The condition is hypothesized to mainly originate from nerve injury. The effects of cold exposure on hand function, the occurrence of cold sensitivity in the general population, the link between cold exposure and cold sensitivity, as well as the interface between cold sensitivity and Raynaud’s phenomenon are not fully understood. Therefore, this thesis was also intended to expand the knowledge on Raynaud’s phenomenon and cold sensitivity. Methods: Postal surveys were sent to a sample of men and women between 18 and 70 years of age, living in Norrbotten, Västerbotten, Västernorrland, and Jämtland, drawn from the national Swedish population register. The first survey collected data on 12,627 subjects, and the results were used to describe cold exposure characteristics, and broadly investigate the statistical associations with different neurological and vascular hand symptoms (Paper I). A follow-up survey was sent to a subset of responders, to form nested case–control studies on cold sensitivity (N=1,230; Paper II) and Raynaud’s phenomenon (N=1,400; Paper III). Subjects with cold sensitivity (N=12) from Paper II were subsequently recruited to a laboratory study, to investigate the vascular and neurosensory function of the hands, by means of physical examination, laser speckle contrast analysis before and after cold stress testing, and thermal quantitative sensory testing (Paper IV). Finally, healthy controls (N=1,239) from the case–control studies were used as a reference population for the Cold intolerance symptom severity questionnaire, to establish a cut-off for abnormal cold sensitivity (Paper V). Results: In Paper I, cold exposure was commonly reported, both during work and leisure time. Exposure was most pronounced in alpine regions, generally higher among men than women, and decreased with age. Highly cold-exposed occupational groups were militaries; agricultural, forestry and fishery workers; and crafts and related trades workers (e.g. construction workers). The correlation between occupational and leisure-time cold climate exposure was low. Men reported more occupational exposure to hand-arm vibration than women, but the correlation between occupational cold and vibration exposure was low. A range of neurological and vascular hand symptoms were statistically associated with high cold exposure, such as decreased perception to touch, warmth, and cold, as well as Raynaud’s phenomenon. In Paper II, cold sensitivity was significantly associated with previous frostbite affecting the hands, rheumatic disease, upper extremity nerve injury, migraine, vascular disease, and high body mass index (inversely), in a multiple conditional logistic regression model. In Paper III, Raynaud’s phenomenon was significantly associated with previous frostbite affecting the hands, first degree heredity, and high body mass index (inversely), in a similar model. Previous upper extremity nerve injury was suggested as a separating trait between Raynaud’s phenomenon and cold sensitivity. In Paper IV, laser speckle contrast analysis indicated disturbances in microvascular regulation, while physical examination and thermal quantitative sensory testing mainly yielded normal results. In Paper V, the 95th percentile for the Cold intolerance symptom severity score was 49.5 for men, and 53.0 for women. Conclusions: Cold exposure in the working-age population of northern Sweden varied with age, gender, occupation, and place of residence. Cold exposure was related to the reporting of neurological and vascular hand symptoms in the population as a whole. There was a major overlap between reporting cold sensitivity and Raynaud’s phenomenon, and the conditions shared several associated factors. Previous upper extremity nerve injury was suggested to be a separating trait, supporting the neurosensory pathophysiological hypothesis for cold sensitivity. Cold sensitivity was not effectively assessed by physical examination or thermal quantitative sensory testing. However, laser speckle contrast analysis could prove a useful tool in further studies on cold sensitivity. A Cold intolerance symptom severity score above 50 could be considered to indicate abnormal cold sensitivity, and be used to guide further care

The impact of Raynaud's phenomenon on work ability : a longitudinal study

OBJECTIVE: To determine if having Raynaud's phenomenon (RP) affects the work ability, job retainment, or occurrence of sick leave. METHODS: Surveys on the working-age general population of northern Sweden were conducted in 2015 and 2021, gathering data on RP, occupation and sick leave. Work ability was assessed using the Work Ability Score. RESULTS: The study population consisted of 2,703 women and 2,314 men, among which 390 women and 290 men reported RP at follow-up. For women, the mean [standard deviation (SD)] Work Ability Score was 8.02 (2.24) for subjects reporting RP and 7.68 (2.46) for those without RP. For men, the corresponding numbers were 7.37 (2.03) and 7.61 (2.14), respectively. Multiple linear regression did not show an association between RP status and work ability (p = 0.459 for women and p = 0.254 for men), after adjusting for age, body mass index, physical workload, cardiovascular disease, and perceived stress. Having retained the same main livelihood since baseline was reported by 227 (58.5%) women with RP, 1,163 (51.2%) women without RP, 152 (52.6%) men with RP, and 1,075 (54.1%) men without RP (p = 0.002 for women and p = 0.127 for men). At follow-up, any occurrence of sick leave during the last year was reported by 80 (21.4%) women with RP, 410 (18.6%) women without RP, 48 (17.1%) men with RP, and 268 (13.7%) men without RP (p = 0.208 for women and p = 0.133 for men). Among those reporting sick leave, the mean (SD) duration in months was 2.93 (3.76) for women with RP, 3.00 (4.64) for women without RP, 2.77 (3.79) for men with RP, and 2.91 (12.45) for men without RP (p = 0.849 for women and p = 0.367 for men). CONCLUSION: For neither women nor men was there a significant effect of having RP on work ability. Women with RP reported a slightly higher job retainment compared to those without the condition, while there was no difference in job retainment among men. For neither gender did the presence of RP influence the occurrence of recent sick leave, nor did it affect the length of time away from work

A prospective study on local cold injuries in northern Sweden

The study aimed to determine the prevalence and incidence proportion of local cold injuries in northern Sweden, and identify associated factors. It was based on prospective data from surveys in 2015 and 2021 sent to a population-based sample in northern Sweden. Multiple binary logistic regression was performed. The study included 5,017 subjects (response rate 44.4%). The prevalence of cold injuries in the hands was 11.4%, feet 12.6%, and face 19.9%, while the incidence proportion was 1.0%, 1.0%, and 0.9%, respectively. Male gender was associated with incident cold injuries in the hands (OR 1.69; 95% CI 1.31–1.28), feet (OR 1.34; 95% CI 1.04–1.73), and face (OR 1.53; 95% CI 1.15–2.03); mental stress with cold injuries in the hands (OR 1.55; 95% CI 1.16–2.05) and feet (OR 1.39; 95% CI 1.04–1.88); previous stroke with cold injuries in the hands (OR 2.64; 95% CI 1.09–6.40) and face (OR 3.09; 95% CI 1.26–7.56); and Raynaud’s phenomenon with cold injuries in the hands (OR 2.48; 95% CI 1.80–3.41) and feet (OR 2.07; 95% CI 1.50–2.87). We conclude that male gender, mental stress, previous stroke, and Raynaud’s phenomenon increased the probability of contracting local cold injuries

Occupational cold exposure is associated with neck pain, low back pain, and lumbar radiculopathy

Ambient cold exposure can pose health risks, and this study was aimed at investigating associations with musculoskeletal disorders. A postal survey was performed on 12,627 men and women, ages 18–70 years, living in northern Sweden. Statistical associations were determined using multiple logistic regression. The study sample consisted of 6,886 women (54.5%), and 5,741 men. Reporting high occupational ambient cold exposure was statistically significantly associated with neck pain (OR 1.36; 95% CI 1.16–1.59), low back pain (OR 1.38; 95% CI 1.17–1.63), and lumbar radiculopathy (OR 1.36; 95% CI 1.07–1.73), after adjusting for age, gender, body mass index, physical work load, daily smoking, and stress. We conclude that ambient cold exposure during work was an independent predictor of neck pain, low back pain, and lumbar radiculopathy. In occupational health care settings, cold exposure should be recognised as a possible risk factor for musculoskeletal disorders. Practitioner summary: This cross-sectional, survey-based study investigated associations between self-reported occupational ambient cold exposure and musculoskeletal disorders. It showed significant associations between high cold exposure and neck pain, low back pain and lumbar radiculopathy. In occupational health care settings, cold exposure should be recognised as a possible risk factor for musculoskeletal disorders

Occupational cold exposure is associated with increased reporting of airway symptoms

Objective: To determine if exposure to cold environments, during work or leisure time, was associated with increased reporting of airway symptoms in the general population of northern Sweden. Methods: Through a population-based postal survey responded to by 12627 subjects, ages 18–70, living in northern Sweden, the occurrence of airway symptoms was investigated. Cold exposure during work or leisure time was self-reported on numerical rating scales. Binary logistic regression was used to determine the statistical association between cold exposure and airway symptoms. Results: For currently working subjects (N=8740), reporting any occupational cold exposure was associated to wheeze (OR 1.3; 95% CI 1.1–1.4); chronic cough (OR 1.2; 95% CI 1.1–1.4); and productive cough (OR 1.3; 95% CI 1.1–1.4), after adjusting for gender, age, body mass index, daily smoking, asthma, and chronic obstructive pulmonary disease. Leisure-time cold exposure was not signifcantly associated to reporting airway symptoms. Conclusions: Occupational cold exposure was an independent predictor of airway symptoms in northern Sweden. Therefore, a structured risk assessment regarding cold exposure could be considered for inclusion in the Swedish workplace legislation

Occupational noise exposure and Raynaud's phenomenon : a nested case-control study

The primary aim of this study was to determine if self-reported occupational noise exposure was associated with Raynaud's phenomenon. In northern Sweden, a nested case-control study was performed on subjects reporting Raynaud's phenomenon (N=461), and controls (N=763) matched by age, sex and geographical location. The response rate to the exposure questionnaire was 79.2%. The study showed no statistically significant association between occupational noise exposure and reporting Raynaud's phenomenon (OR 1.10; 95% CI 0.83-1.46) in simple analyses. However, there was a trend towards increasing OR for Raynaud's phenomenon with increasing noise exposure, although not statistically significant. Also, there was a significant association between noise exposure and hearing loss (OR 2.76; 95% CI 2.00-3.81), and hearing loss was associated with reporting Raynaud's phenomenon (OR 1.52; 95% CI 1.03-2.23) in a multiple regression model. In conclusion, self-reported occupational noise exposure was not statistically significantly associated with Raynaud's phenomenon, but there was a dose-effect trend. In addition, the multiple model showed a robust association between hearing loss and Raynaud's phenomenon. These findings offer some support for a common pathophysiological background for Raynaud's phenomenon and hearing loss among noise-exposed workers, possibly through noise-induced vasoconstriction

The association between cold exposure and musculoskeletal disorders : a prospective population-based study

Objectives: The aim of the study was to determine the association between occupational ambient cold exposure and neck–shoulder pain (NSP), low back pain (LBP), and radiating LBP. Methods: The study cohort comprised of 3,843 working subjects in northern Sweden who answered a baseline (spring 2015) and a follow-up questionnaire (spring 2021). NSP, LBP, and radiating LBP were assessed in both surveys. Occupational cold exposure was assessed at baseline, on a whole number numerical rating scale (NRS) and categorized in quartiles. Binary logistic regression determined the association between cold exposure at baseline and incident NSP, LBP, and radiating LBP, adjusted for age, gender, body mass index, smoking, mental stress, and physical workload. Results: There were statistically significant associations between high occupational ambient cold exposure (NRS 5–7 and NRS 8–10) and NSP (1.59; 95% CI 1.08–2.33 and OR 1.50; 95% CI 1.03–2.19); NRS 8–10 and LBP (OR 1.61; 95% CI 1.13–2.29); and NRS 5–7 and radiating LBP (OR 1.87; 95% CI 1.12–3.16). Gender-stratified analyses showed statistically significant associations between high occupational ambient cold exposure (NRS 5–7 and NRS 8–10) and NSP (OR 1.97; 95% CI 1.07–3.61 and OR 1.97; 95% CI 1.06–3.67) for men and between NRS 8–10 and LBP (OR 1.82; 95% CI 1.14–2.91) and NRS 5–7 and radiating LBP (OR 2.20; 95% CI 1.15–4.24) for women. Conclusions: Occupational ambient cold exposure was associated with NSP, LBP, and radiating LBP, and should be recognised as a possible occupational risk factor