Determinants of international variation in the prevalence of disabling wrist and hand pain

Background

Previous research has indicated that wide international variation in the prevalence of disabling low back pain among working populations is largely driven by factors predisposing to musculoskeletal pain more generally. This paper explores whether the same applies to disabling wrist/hand pain (WHP).

Methods

Using data from the Cultural and Psychosocial Influences on Disability (CUPID) study, we focused on workers from 45 occupational groups (office workers, nurses and other workers) in 18 countries. Among 11,740 participants who completed a baseline questionnaire about musculoskeletal pain and potential risk factors, 9082 (77%) answered a further questionnaire after a mean interval of 14 months, including 1373 (15%) who reported disabling WHP in the month before follow-up. Poisson regression was used to assess associations of this outcome with baseline risk factors, including the number of anatomical sites other than wrist/hand that had been painful in the 12 months before baseline (taken as an index of general propensity to pain).

Results

After allowance for other risk factors, the strongest associations were with general pain propensity (prevalence rate ratio for an index ≥6 vs. 0: 3.6, 95% confidence interval 2.9–4.4), and risk rose progressively as the index increased. The population attributable fraction for a pain propensity index > 0 was 49.4%. The prevalence of disabling WHP by occupational group ranged from 0.3 to 36.2%, and correlated strongly with mean pain propensity index (correlation coefficient 0.86).

Conclusion

Strategies to prevent disability from WHP among working populations should explore ways of reducing general propensity to pain, as well as improving the ergonomics of occupational tasks.

Descriptive Epidemiology of Somatising Tendency: Findings from the CUPID Study

Somatising tendency, defined as a predisposition to worry about common somatic symptoms, is importantly associated with various aspects of health and health-related behaviour, including musculoskeletal pain and associated disability. To explore its epidemiological characteristics, and how it can be specified most efficiently, we analysed data from an international longitudinal study. A baseline questionnaire, which included questions from the Brief Symptom Inventory about seven common symptoms, was completed by 12,072 participants aged 20-59 from 46 occupational groups in 18 countries (response rate 70%). The seven symptoms were all mutually associated (odds ratios for pairwise associations 3.4 to 9.3), and each contributed to a measure of somatising tendency that exhibited an exposure-response relationship both with multi-site pain (prevalence rate ratios up to six), and also with sickness absence for non-musculoskeletal reasons. In most participants, the level of somatising tendency was little changed when reassessed after a mean interval of 14 months (75% having a change of 0 or 1 in their symptom count), although the specific symptoms reported at follow-up often differed from those at baseline. Somatising tendency was more common in women than men, especially at older ages, and varied markedly across the 46 occupational groups studied, with higher rates in South and Central America. It was weakly associated with smoking, but not with level of education. Our study supports the use of questions from the Brief Symptom Inventory as a method for measuring somatising tendency, and suggests that in adults of working age, it is a fairly stable trait.

Additional perspectives on chronic kidney disease of unknown aetiology (CKDu) in Sri Lanka--lessons learned from the WHO CKDu population prevalence study

The recent emergence of an apparently new form of chronic kidney disease of unknown aetiology (CKDu) has become a serious public health crisis in Sri Lanka. CKDu is slowly progressive, irreversible, and asymptomatic until late stages, and is not attributable to hypertension, diabetes, or other known aetiologies. In response to the scope and severity of the emerging CKDu health crisis, the Sri Lanka Ministry of Health and the World Health Organization initiated a collaborative research project from 2009 through 2012 to investigate CKDu prevalence and aetiology. The objective of this paper is to discuss the recently published findings of this investigation and present additional considerations and recommendations that may enhance subsequent investigations designed to identify and understand CKDu risk factors in Sri Lanka or other countries.

Additional perspectives on chronic kidney disease of unknown aetiology (CKDu) in Sri Lanka--lessons learned from the WHO CKDu population prevalence study

The recent emergence of an apparently new form of chronic kidney disease of unknown aetiology (CKDu) has become a serious public health crisis in Sri Lanka. CKDu is slowly progressive, irreversible, and asymptomatic until late stages, and is not attributable to hypertension, diabetes, or other known aetiologies. In response to the scope and severity of the emerging CKDu health crisis, the Sri Lanka Ministry of Health and the World Health Organization initiated a collaborative research project from 2009 through 2012 to investigate CKDu prevalence and aetiology. The objective of this paper is to discuss the recently published findings of this investigation and present additional considerations and recommendations that may enhance subsequent investigations designed to identify and understand CKDu risk factors in Sri Lanka or other countries.

Disabling musculoskeletal pain in working populations: is it the job, the person, or the culture?

To compare the prevalence of disabling low back pain (DLBP) and disabling wrist/hand pain (DWHP) among groups of workers carrying out similar physical activities in different cultural environments, and to explore explanations for observed differences, we conducted a cross-sectional survey in 18 countries. Standardised questionnaires were used to ascertain pain that interfered with everyday activities and exposure to possible risk factors in 12,426 participants from 47 occupational groups (mostly nurses and office workers). Associations with risk factors were assessed by Poisson regression. The 1-month prevalence of DLBP in nurses varied from 9.6% to 42.6%, and that of DWHP in office workers from 2.2% to 31.6%. Rates of disabling pain at the 2 anatomical sites covaried (r = 0.76), but DLBP tended to be relatively more common in nurses and DWHP in office workers. Established risk factors such as occupational physical activities, psychosocial aspects of work, and tendency to somatise were confirmed, and associations were found also with adverse health beliefs and group awareness of people outside work with musculoskeletal pain. However, after allowance for these risk factors, an up-to 8-fold difference in prevalence remained. Systems of compensation for work-related illness and financial support for health-related incapacity for work appeared to have little influence on the occurrence of symptoms. Our findings indicate large international variation in the prevalence of disabling forearm and back pain among occupational groups carrying out similar tasks, which is only partially explained by the personal and socioeconomic risk factors that were analysed.

Musculoskeletal pain in four occupational populations in Sri Lanka

BACKGROUND

Factors influencing work-related musculoskeletal disorders might differ in developing and developed countries.

AIMS

To assess the prevalence and determinants of musculoskeletal pain in four occupational populations in Sri Lanka.

METHODS

As part of the international Cultural and Psychosocial Influences on Disability study, samples of postal workers, sewing machinists, nurses and computer operators were interviewed about pain at each of six anatomical sites in the past month, and about possible physical and psychosocial risk factors. Associations with prevalent pain were assessed by binomial regression.

RESULTS

Analysis was based on 852 participants (86% response rate). Overall, the lower back was the most common site of pain, with 1-month prevalence ranging from 12% in computer operators to 30% in nurses. Postal workers had the highest prevalence of shoulder pain (23%), but pain in the wrist/hand was relatively uncommon in all four occupational groups (prevalence rates ranged from 8% to 9%). Low mood and tendency to somatize were consistently associated with pain at all six sites. After adjustment for psychosocial risk factors, there was a higher rate of low back pain in nurses and postal workers than in computer operators, a higher rate of shoulder pain in postal workers than in the other occupational populations, and a relatively low rate of knee pain in computer operators.

CONCLUSIONS

Rates of regional pain, especially at the wrist/hand, were lower than have been reported in Western countries. As elsewhere, pain was strongly associated with low mood and somatizing tendency. Differences in patterns of pain by occupation may reflect differences in physical activities.

The CUPID (Cultural and Psychosocial Influences on Disability) study: methods of data collection and characteristics of study sample

Background

The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.

Methods/Principal Findings

A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).

Conclusions/Significance

The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively.

Chronic kidney disease of unknown aetiology in Sri Lanka: is cadmium a likely cause?

Background

The rising prevalence of chronic kidney disease (CKD) and subsequent end stage renal failure necessitating renal replacement therapy has profound consequences for affected individuals and health care resources. This community based study was conducted to identify potential predictors of microalbuminuria in a randomly selected sample of adults from the North Central Province (NCP) of Sri Lanka, where the burden of CKD is pronounced and the underlying cause still unknown.

Methods

Exposures to possible risk factors were determined in randomly recruited subjects (425 females and 461 males) from selected areas of the NCP of Sri Lanka using an interviewer administered questionnaire. Sulphosalicylic acid and the Light Dependent Resister microalbumin gel filtration method was used for initial screening for microalbuminuria and reconfirmed by the Micral strip test.

Results

Microalbumnuria was detected in 6.1% of the females and 8.5% of the males. Smoking (p < 0.001), alcohol use (p = 0.003), hypertension (p < 0.001), diabetes (p < 0.001), urinary tract infection (UTI) (p = 0.034) and consumption of water from wells in the fields (p = 0.025) were associated with microalbuminuria. In the binary logistic regression analysis, hypertension, diabetes mellitus, UTI, drinking well water in the fields, smoking and pesticide spraying were found to be significant predictors of microalbuminuria.

Conclusions

Hypertension, diabetes mellitus, UTI, and smoking are known risk factors for microalbuminuria. The association between microalbuminuria and consumption of well water suggests an environmental aetiology to CKD in NCP. The causative agent is yet to be identified. Investigations for cadmium as a potential causative agent needs to be initiated.

Chronic kidney disease of unknown aetiology in Sri Lanka: is cadmium a likely cause?

BACKGROUND

The rising prevalence of chronic kidney disease (CKD) and subsequent end stage renal failure necessitating renal replacement therapy has profound consequences for affected individuals and health care resources. This community based study was conducted to identify potential predictors of microalbuminuria in a randomly selected sample of adults from the North Central Province (NCP) of Sri Lanka, where the burden of CKD is pronounced and the underlying cause still unknown.

METHODS

Exposures to possible risk factors were determined in randomly recruited subjects (425 females and 461 males) from selected areas of the NCP of Sri Lanka using an interviewer administered questionnaire. Sulphosalicylic acid and the Light Dependent Resister microalbumin gel filtration method was used for initial screening for microalbuminuria and reconfirmed by the Micral strip test.

RESULTS

Microalbumnuria was detected in 6.1% of the females and 8.5% of the males. Smoking (p < 0.001), alcohol use (p = 0.003), hypertension (p < 0.001), diabetes (p < 0.001), urinary tract infection (UTI) (p = 0.034) and consumption of water from wells in the fields (p = 0.025) were associated with microalbuminuria. In the binary logistic regression analysis, hypertension, diabetes mellitus, UTI, drinking well water in the fields, smoking and pesticide spraying were found to be significant predictors of microalbuminuria.

CONCLUSIONS

Hypertension, diabetes mellitus, UTI, and smoking are known risk factors for microalbuminuria. The association between microalbuminuria and consumption of well water suggests an environmental aetiology to CKD in NCP. The causative agent is yet to be identified. Investigations for cadmium as a potential causative agent needs to be initiated.

Impact of low-level exposure to organophosphates on human reproduction and survival

Despite their widespread and longstanding use for the public good, organophosphate (OP) pesticides have led to many adverse effects on human health. Environmental exposure to OPs and adverse reproductive outcomes in men and women working on or living near farms are increasingly reported worldwide. The aim of the current review is to determine whether exposure to OPs, at levels lower than that which results in clinical manifestations of acute OP poisoning, leads to an adverse impact on fertility, growth and development, and to highlight possible effects for further investigation. There is evidence of impaired fertility due to a reduction in semen quality and possibly lower testosterone levels in exposed males. There is also evidence of impairment of fetal growth and development brought about by prenatal exposure to OPs. Paraoxonase gene (PON1) activity in the fetus and during early childhood makes the fetus and child more vulnerable to OP poisoning, suggesting that OP exposure has a greater impact on fetal and infant growth and development than on adults when exposed to the same concentrations of pesticides. This review raises concerns that exposure to OP pesticides at levels currently regarded as safe adversely affect human reproductive function and survival.

Chronic renal failure in North Central Province of Sri Lanka: an environmentally induced disease

This study was conducted to determine the aetiology of chronic renal failure (CRF) in the North Central Province of Sri Lanka. Patients (n=183) with CRF of unknown aetiology were compared with controls (n=200) who had no evidence of chronic renal dysfunction. Exposure to possible risk factors were determined by an interviewer-administered questionnaire. Being a farmer (P<0.001), using pesticides (P<0.001), drinking well water (P<0.001), a family history of renal dysfunction (P=0.001), use of ayurvedic treatment (P<0.001) and a history of snake bite (P<0.001) were risk factors for CRF of unknown aetiology. Using logistic regression analysis, a family history of chronic renal disease, taking ayurvedic treatment and history of snake bite were found to be significant predictors for CRF of unknown aetiology. There is evidence to support an environmental aetiology to CRF in Sri Lanka.

Neurological symptoms among Sri Lankan farmers occupationally exposed to acetylcholinesterase-inhibiting insecticides

BACKGROUND

In many agricultural districts in Sri Lanka, pesticide poisoning is a leading cause of death. This study aims to evaluate the impact of pesticide use on Sri Lankan farmers' health.

METHODS

A total of 260 subjects were surveyed in both a low and a high exposure period. Acetylcholinesterase activity was measured and data on symptoms were collected with questionnaires.

RESULTS

Twenty-four percent of surveyed farmers had suffered at least once from acute pesticide poisoning. Farmers showed significantly more inhibition of cholinesterase activity than controls. Acute symptoms indicative for exposure to cholinesterase-inhibiting pesticides were associated with farming and a higher degree of cholinesterase suppression (more than 13% inhibition). Integrated Pest Management (IPM) training seemed to result in less insecticide use, and less cholinesterase inhibition.

CONCLUSIONS

Our results suggest that occupational acetylcholinesterase-inhibiting insecticide exposures have a negative impact on Sri Lankan farmers' health. Overall reduction in pesticide use seems the best option to protect farmers from the adverse effects of pesticides.