Modification of the Revised National Institute for Occupational Safety and Health (NIOSH) Lifting Equation to Determine the Individual Manual Lifting Risk in Malaysia's Manufacturing Industry.

INTRODUCTION: The National Institute for Occupational Safety and Health (NIOSH) established the Revised NIOSH Lifting Equation (RNLE) for manual lifting risk assessment. The objectives of this study were to determine the characteristics of physical factors using the RNLE and to explore additional factors to RNLE by modifying it to an Individual Lifting Equation (ILE). METHODS: This cross-sectional study was conducted in the manufacturing industry of three states in Malaysia among manual lifting workers. A questionnaire was administered, which comprised the sociodemographic characteristics and Nordic Musculoskeletal Questionnaire (NMQ) assessing low back pain (LBP). The RNLE dataset includes a load constant and six manual lifting variables collected from observational ergonomic risk assessment. The RNLE was modified to ILE by incorporating age, gender, and BMI. The equations' Lifting Index (LI) computed provides an overall manual lifting risk estimate. RESULTS: There were 165 participants, with a mean age of 28 years, and 108 (65.5%) were male. Most participants had a BMI within the normal range (60 (36.4%)) or were classified as overweight (54 (32.7%)). The lifting horizontal location showed the highest risk estimates, with the lowest mean multiplier value of 0.55. In contrast, age and BMI had the lowest risk estimates, with mean multiplier values of 0.99 and 0.98, respectively. Among the participants, LI values of one or less, indicating very low risk, were observed in 58 (35.1%) for RNLE and 39 (23.6%) for ILE. Additionally, RNLE and ILE showed figures of 11 (6.7%) and 20 (12.1%), respectively, signifying a very high risk of LI exceeding three. CONCLUSION: Studying the lifting factors and equation multipliers from RNLE is critical for evaluating the risk estimates of manual lifting. Exploring the ILE based on individual characteristics is appropriate to support the ergonomic program. Further study is needed to validate the ILE as an accurate screening tool for determining LBP risk estimates.

Association between night-shift work, sleep quality and health-related quality of life: a cross-sectional study among manufacturing workers in a middle-income setting.

OBJECTIVES: Night-shift work may adversely affect health. This study aimed to determine the impact of night-shift work on health-related quality of life (HRQoL), and to assess whether sleep quality was a mediating factor. DESIGN: A cross-sectional study. SETTING: 11 manufacturing factories in Malaysia. PARTICIPANTS: 177 night-shift workers aged 40-65 years old were compared with 317 non-night-shift workers. PRIMARY AND SECONDARY OUTCOMES: Participants completed a self-administered questionnaire on socio-demographics and lifestyle factors, 12-item Short Form Health Survey V.2 (SF-12v2) and the Pittsburgh Sleep Quality Index (PSQI). The Baron and Kenny's method, Sobel test and multiple mediation model with bootstrapping were applied to determine whether PSQI score or its components mediated the association between night-shift work and HRQoL. RESULTS: Night-shift work was associated with sleep impairment and HRQoL. Night-shift workers had significantly lower mean scores in all the eight SF-12 domains (p<0.001). Compared with non-night-shift workers, night-shift workers were significantly more likely to report poorer sleep quality, longer sleep latency, shorter sleep duration, sleep disturbances and daytime dysfunction (p<0.001). Mediation analyses showed that PSQI global score mediated the association between night-shift work and HRQoL. 'Subjective sleep quality' (indirect effect=-0.24, SE=0.14 and bias corrected (BC) 95% CI -0.58 to -0.01) and 'sleep disturbances' (indirect effect=-0.79, SE=0.22 and BC 95% CI -1.30 to -0.42) were mediators for the association between night-shift work and physical well-being, whereas 'sleep latency' (indirect effect=-0.51, SE=0.21 and BC 95% CI -1.02 to -0.16) and 'daytime dysfunction' (indirect effect=-1.11, SE=0.32 and BC 95% CI -1.86 to -0.58) were mediators with respect to mental well-being. CONCLUSION: Sleep quality partially explains the association between night-shift work and poorer HRQoL. Organisations should treat the sleep quality of night-shift workers as a top priority area for action to improve their employees' overall wellbeing.

Association between night-shift work, sleep quality and metabolic syndrome.

OBJECTIVES: Occupational factors, particularly night-shift work, are attracting growing interest as a possible determinant of metabolic syndrome (MetS). This study aimed to determine the association between night-shift work and MetS, and assess whether sleep quality is a mediating factor. METHODS: A cross-sectional study was conducted among Malaysian manufacturing workers, aged 40-65 years old. They completed a self-administered questionnaire on sociodemographics, lifestyle and family history, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Waist circumference, blood pressure, fasting blood sugar, triglycerides and high-density lipoprotein levels were measured. Baron and Kenny's method, Sobel test and multiple mediation models with bootstrapping were used to determine whether the PSQI global score or its components mediated the association between night-shift work and MetS. RESULTS: Of the 494 participants, 177 (36%) worked night shift and 51% were men. The prevalence of MetS was 37%. Night-shift work was independently associated with a twofold increase in the risk of MetS (adjusted OR: 1.92, 95% CI 1.24 to 2.97). However, the association between night-shift work and MetS did not appear to be modified by sex. Night-shift workers also reported significantly poorer sleep quality, longer sleep latency, shorter sleep duration, sleep disturbances and daytime dysfunction. Robust mediation analysis nonetheless showed that neither PSQI global score nor its components mediated the association between night-shift work and MetS. CONCLUSION: Early screening and management of MetS and the development of programmes to improve sleep quality should be carried out among night-shift workers. Future research should investigate other modifiable mediators linking night-shift work and MetS.

Predictors of handgrip strength among adults of a rural community in Malaysia.

Handgrip strength is useful for screening the nutritional status of adult population as it is strongly associated with physical disabilities and mortality. Therefore, we aimed to determine the predictors of handgrip strength among adults of a rural community in Malaysia using a cross-sectional study design with multistage sampling. All adults aged 30 years and older from 1250 households were invited to our study. Structured questionnaire on sociodemographic characteristics, medical history, occupation history, lifestyle practices, and measurements, including anthropometry and handgrip strength were taken. There were 2199 respondents with 55.2% females and majority were of Malay ethnicity. Their mean (standard deviation) age was 53.4 (13.2) years. The response rate for handgrip strength was 94.2%. Females had significantly lower handgrip strength than males (P < .05). In the multiple linear regression models, significant predictors of handgrip strength for males were age, height, job groups, and diabetes, while for females, the significant predictors were age, weight, height, and diabetes.

Noise-induced hearing loss and associated factors among vector control workers in a Malaysian state.

This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers.

A comparison of hand-arm vibration syndrome between Malaysian and Japanese workers.

OBJECTIVES: The aim of this study was to investigate the clinical characteristics of HAVS in a tropical environment in comparison with a temperate environment. METHODS: We conducted a series medical examinations among the forestry, construction and automobile industry workers in Malaysia adopting the compulsory medical examination procedure used by Wakayama Medical University for Japanese vibratory tools workers. We matched the duration of vibration exposure and compared our results against the Japanese workers. We also compared the results of the Malaysian tree fellers against a group of symptomatic Japanese tree fellers diagnosed with HAVS. RESULTS: Malaysian subjects reported a similar prevalence of finger tingling, numbness and dullness (Malaysian=25.0%, Japanese=21.5%, p=0.444) but had a lower finger skin temperature (FST) and higher vibrotactile perception threshold (VPT) values as compared with the Japanese workers. No white finger was reported in Malaysian subjects. The FST and VPT of the Malaysian tree fellers were at least as bad as the Japanese tree fellers despite a shorter duration (mean difference=20.12 years, 95%CI=14.50, 25.40) of vibration exposure. CONCLUSIONS: Although the vascular disorder does not manifest clinically in the tropical environment, the severity of HAVS can be as bad as in the temperate environment with predominantly neurological disorder. Hence, it is essential to formulate national legislation for the control of the occupational vibration exposure.

Dose-response relationship between hand-transmitted vibration and hand-arm vibration syndrome in a tropical environment.

OBJECTIVES: The dose-response relationship for hand-transmitted vibration has been investigated extensively in temperate environments. Since the clinical features of hand-arm vibration syndrome (HAVS) differ between the temperate and tropical environment, we conducted this study to investigate the dose-response relationship of HAVS in a tropical environment. METHODS: A total of 173 male construction, forestry and automobile manufacturing plant workers in Malaysia were recruited into this study between August 2011 and 2012. The participants were interviewed for history of vibration exposure and HAVS symptoms, followed by hand functions evaluation and vibration measurement. Three types of vibration doses-lifetime vibration dose (LVD), total operating time (TOT) and cumulative exposure index (CEI)-were calculated and its log values were regressed against the symptoms of HAVS. The correlation between each vibration exposure dose and the hand function evaluation results was obtained. RESULTS: The adjusted prevalence ratio for finger tingling and numbness was 3.34 (95% CI 1.27 to 8.98) for subjects with lnLVD≥20 ln m(2) s(-4) against those <16 ln m(2) s(-4). Similar dose-response pattern was found for CEI but not for TOT. No subject reported white finger. The prevalence of finger coldness did not increase with any of the vibration doses. Vibrotactile perception thresholds correlated moderately with lnLVD and lnCEI. CONCLUSIONS: The dose-response relationship of HAVS in a tropical environment is valid for finger tingling and numbness. The LVD and CEI are more useful than TOT when evaluating the dose-response pattern of a heterogeneous group of vibratory tools workers.

Prevalence and associated factors of stress in the Malaysian Police Force.

OBJECTIVE: This study aims to determine the prevalence of stress and the associated socio-demographic and work factors among police personnel in Metropolitan Kuala Lumpur, Malaysia. METHOD: A cross-sectional study was conducted in two randomly selected police districts in Kuala Lumpur from 2009 to 2011. A total of 579 police officers from 11 police stations and two headquarters participated in this study. The 21-item Depression, Anxiety and Stress questionnaire was used. Multinomial logistic regression analyses were carried out to examine the effect of socio-demographic and work factors on stress. RESULTS: The overall prevalence of stress was 38.8% (95% CI 34.2, 43.6) with 5.9% (3.9, 8.8), 14.9% (11.6, 18.8) and 18.0% (14.5, 22.2) for severe, moderate and mild stress, respectively. Inspectors were more likely to suffer from severe stress (aOR 10.68, 95% CI 3.51, 32.53) compared to junior officers. Those who complained that their salaries were not commensurate with their jobs were more likely to suffer from moderate levels of stress (aOR 2.73, 95% CI 1.43, 5.22) compared to those who were happy with their salaries. CONCLUSIONS: This study strengthens findings that police job is stressful. Special attention needs to be paid to Inspector-level ranks and the remuneration structure of police officers to address this issue.

The clinical features of hand-arm vibration syndrome in a warm environment--a review of the literature.

UNLABELLED: The internationally accepted limit values and the health effects of hand-transmitted vibration exposure have been described extensively in the literature from temperate climate countries but not from a tropical climate environment. OBJECTIVES: We conducted a systematic review of the health effects of hand-transmitted vibration exposure in tropical countries to determine the characteristics of hand-arm vibration syndrome in a warm environment and compared the findings with the results of the systematic reviews published by the US NIOSH. METHODS: We searched major medical databases including MEDLINE, PubMed, Embase, CINAHL, Ovid and Cochrane based on the terms "hand arm vibration syndrome," "hand transmitted vibration," "vibration white finger" and "Raynaud" up to January 2011. Only studies conducted in a tropical or subtropical environment were selected for the review. The quality of the selected papers was assessed independently by two investigators using predefined criteria. A standard set of information was abstracted from the papers for review. RESULTS: Only six papers from tropical countries and three papers from subtropical countries were available in the literature. No vibration white finger was reported in the tropical countries. Neurological symptoms were prevalent in the vibration-exposed workers. Finger coldness seems to be an important surrogate for vascular disorder in a tropical environment. Meta-analysis could not be performed due to inadequacy of the information reported in these papers. CONCLUSIONS: The current dose-response relationship in ISO5349-1 for hand-transmitted vibration exposure is not applicable to a tropical environment. Further studies on hand-arm vibration syndromes in tropical countries are needed.

Salivary biomarkers of stress among teachers in an urban setting.

The aim of this study was to determine the prevalence of job stress among secondary school teachers using Karasek Job Content Questionnaire (JCQ), the association between salivary cortisol, salivary IgA, and sociodemographic characteristics, and the association between log cortisol, IgA levels, and job strain categories. A cross-sectional study was undertaken using JCQ and salivary cortisol and IgA samples. Cluster sampling was done yielding 302 respondents. The prevalence of stress among all teachers was 20.2%. Being a Malay, teaching experience of 5 to 10 years, and those without a supervisor's support had higher prevalence of high job strain. Teachers in the 31 to 40 years age bracket, educating handicapped children with the absence of supervisor support exhibited higher stress levels with lower log salivary IgA levels. Further studies must be conducted using salivary biomarkers to study the in-depth relationship of stress, extending into other occupational groups.

Work related determinants of breastfeeding discontinuation among employed mothers in Malaysia.

BACKGROUND: This cross-sectional study assesses factors that contribute to discontinuing breastfeeding among employed mothers in Malaysia. METHODS: A structured questionnaire was used in conducting this study involving all government health clinics in Petaling district between July and September 2006. Respondents were Malaysian women with children between the ages of six to twelve months who were formally employed. Factors studied were selected socio-demographic and work-related characteristics. RESULTS: From a total of 290 respondents, 51% discontinued breastfeeding. The majority (54%) of mothers who discontinued breastfeeding had breastfed their babies for less than three months. Compared to Malay mothers, the risk of breastfeeding discontinuation were higher among Chinese (AOR 3.7, 95% CI: 1.7, 7.8) and Indian mothers (AOR 7.3, 95% CI 1.9, 27.4). Not having adequate breastfeeding facilities at the workplace was also a risk factor for breastfeeding discontinuation (AOR 1.8, 95% CI: 1.05, 3.1). CONCLUSION: It is important that workplaces provide adequate breastfeeding facilities such as a room in which to express breast milk and a refrigerator, and allow mothers flexible time to express breast milk.