Thin-fat insulin-resistant phenotype also present in South Asian neonates born in the Netherlands.

Several studies have shown that South Asian neonates have a characteristic thin-fat insulin-resistant phenotype. The aim of our study was to determine whether this phenotype is also present in South Asians who have migrated to a Western country (the Netherlands). South Asian and white Dutch pregnant women were included in our study. After delivery, cord blood was collected and neonatal anthropometry was measured within 72 h. Compared with white Dutch mothers, South Asian mothers were younger (28.5 v. 32.2 years, P<0.001) and had a higher prepregnancy body mass index (25.1 v. 23.0, P=0.001). Gestational age at delivery was on average 4 days shorter in South Asians (274.9 v. 278.8, P=0.001). To compare the two groups of neonates, we calculated sex- and gestation-specific s.d. scores using the values for mean and s.d. obtained from the white Dutch subjects as a reference. All measurements were smaller in South Asian neonates, except for those of the skinfolds. The largest difference was found in abdominal circumference (s.d. score 1.39, 95% CI -1.76 to -1.01). Triceps and subscapular skinfolds were similar in both groups (triceps s.d. score -0.34, 95% CI -0.88 to +0.20 and subscapular s.d. score -0.03, 95% CI -0.31 to +0.25). South Asian neonates had higher cord plasma levels of triglycerides (0.40 v. 0.36, P=0.614), glucose (5.4 v. 4.8, P=0.079) and insulin (6.3 v. 4.0, P=0.051). However, these differences were not statistically significant. After adjustment for birth weight, the difference in insulin became statistically significant (P=0.001). We therefore conclude that the thin-fat insulin-resistant phenotype is also present in South Asian neonates in the Netherlands.

Neonatal anthropometry: thin-fat phenotype in fourth to fifth generation South Asian neonates in Surinam.

We assessed whether the earlier described 'thin-fat phenotype' is present in Surinam South Asian babies of the fourth to fifth generation after migration from India. In this observational study we collected data from 39 South Asian term neonates and their mothers in Paramaribo, Surinam. We compared the following data with data from an earlier study in Southampton, UK (338 neonates) and in Pune, India (631 neonates): maternal body mass index, neonatal weight, length, head, mid-upper arm and abdominal circumferences and subscapular skinfold thickness. The mothers in Paramaribo were older than the Southampton mothers; their body mass index was comparable. Mean birth weight was 3159 g (Southampton: 3494 g; Pune: 2666 g). Compared with Southampton babies, the Paramaribo babies were smaller in nearly all body measurements, the smallest being abdominal circumference at the umbilicus level (s.d. score: -1.62; 95% confidence interval (CI): -2.07 to -1.16) and mid-upper arm circumference (s.d. score: -1.08; 95% CI: -1.46 to -0.69). In contrast, subscapular skinfold thickness was similar (s.d. score: +0.08; 95% CI: -0.24 to +0.55). Except for subscapular skinfold thickness and length, all neonatal measurements were intermediate between those from Southampton and Pune. The thin-fat phenotype is preserved in Surinam South Asian neonates of the fourth to fifth generation after migration from India.

Physical capacity in relation to low back, neck, or shoulder pain in a working population.

AIMS: To investigate the longitudinal relation between physical capacity (isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine) and low back, neck, and shoulder pain. METHODS: In this prospective cohort study, 1789 Dutch workers participated. At baseline, isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine were measured in the pain free workers, as well as potential confounders, including physical workload. Low back, neck, and shoulder pain were self-reported annually at baseline and three times during follow up. RESULTS: After adjustment for confounders, Poisson generalised estimation equations showed an increased risk of low back pain among workers in the lowest sex specific tertile of performance in the static back endurance tests compared to workers in the reference category (RR = 1.42; 95% CI 1.19 to 1.71), but this was not found for isokinetic trunk lifting strength or mobility of the spine. An increased risk of neck pain was shown for workers with low performance in tests of isokinetic neck/shoulder lifting strength (RR = 1.31; 95% CI 1.03 to 1.67) and static neck endurance (RR = 1.22; 95% CI 1.00 to 1.49). Among workers in the lowest tertiles of isokinetic neck/shoulder lifting strength or endurance of the shoulder muscles, no increased risk of shoulder pain was found. CONCLUSIONS: The findings of this study suggest that low back or neck endurance were independent predictors of low back or neck pain, respectively, and that low lifting neck/shoulder strength was an independent predictor of neck pain. No association was found between lifting trunk strength, or mobility of the spine and the risk of low back pain, nor between lifting neck/shoulder strength or endurance of the shoulder muscles and the risk of shoulder pain.

Effect of sporting activity on absenteeism in a working population.

OBJECTIVES: To determine the effects of sporting activity on absenteeism in a working population. METHODS: Data were used from a prospective cohort study in a working population with a follow up period of 3 years and were collected with yearly questionnaires or collected from company records. Complete data on absenteeism, sporting activity, and potential confounders were collected for 1228 workers. ANOVA was used to test differences in frequency and duration of absenteeism, correlations were computed to measure the association between number of sporting years (divided by age) and frequency and duration of absenteeism, and survival analysis, according to the Cox proportional hazards model, was used to test differences in relative risk at absenteeism and recovery. All analyses were adjusted for age, gender, smoking, and alcohol consumption, and were stratified for employees with sedentary and with more active jobs. RESULTS: ANOVA showed a statistically significant higher mean duration of absenteeism among employees not practicing sports, of approximately 20 days over a period of 4 years. The survival analysis showed an increased relative risk at absenteeism (relative risk (RR) 1.09; confidence interval (CI) 1.01 to 1.18) and a decreased relative risk at recovery (RR 0.90; CI 0.85 to 0.95) for employees not practicing sports. The effect of sporting activity is larger in employees with sedentary work. No associations were found between number of sporting years and absenteeism. CONCLUSION: Employees practicing sports take sick leave significantly less often than their colleagues not practicing sports, while their periods of sick leave are shorter, especially when their work is sedentary.

High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: results of a prospective cohort study.

OBJECTIVE: To determine whether physical and psychosocial load at work influence sickness absence due to low back pain. METHODS: The research was a part of the study on musculoskeletal disorders, absenteeism, stress, and health (SMASH), a 3 year prospective cohort study on risk factors for musculoskeletal disorders. Workers from 21 companies located throughout The Netherlands participated in the part of this study on sickness absence due to low back pain. The study population consisted of 732 workers with no sickness absences of 3 days or longer due to low back pain in the 3 months before the baseline survey and complete data on the reasons for absences during the follow up period. The mean (range) period of follow up in this group was 37 (7-44) months. Physical load at work was assessed by analyses of video recordings. Baseline information on psychosocial work characteristics was obtained by a questionnaire. Data on sickness absence were collected from company records. The main outcome measure was the rate of sickness absences of 3 days or longer due to low back pain during the follow up period. RESULTS: After adjustment of the work related physical and psychosocial factors for each other and for other potential determinants, significant rate ratios ranging from 2.0 to 3.2 were found for trunk flexion, trunk rotation, lifting, and low job satisfaction. A dose-response relation was found for trunk flexion, but not for trunk rotation or lifting. Non-significant rate ratios of about 1.4 were found for low supervisor support and low coworker support. Quantitative job demands, conflicting demands, decision authority, and skill discretion showed no relation with sickness absence due to low back pain. CONCLUSIONS: Flexion and rotation of the trunk, lifting, and low job satisfaction are risk factors for sickness absence due to low back pain. Some indications of a relation between low social support, either from supervisors or coworkers, and sickness absence due to low back pain are also present.

High quantitative job demands and low coworker support as risk factors for neck pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among 1334 workers was conducted. OBJECTIVE: To determine whether the work-related psychosocial factors of quantitative job demands, conflicting job demands, skill discretion, decision authority, supervisor support, coworker support, and job security are risk factors for neck pain. SUMMARY OF BACKGROUND DATA: Among the various risk factors for neck pain, work-related psychosocial factors play a major role. Previous studies on risk factors for neck pain often had a cross-sectional design, and did not take both physical and psychosocial factors into account. METHODS: At baseline, data on work-related psychosocial factors were collected by means of a questionnaire. During the 3-year follow-up period, data on the occurrence of neck pain were collected by means of postal questionnaires. Individuals without neck pain at baseline were selected for the analyses. Cox regression analysis was applied to examine the relation between the work-related psychosocial factors and the cumulative incidence of neck pain. Adjustments were made for various physical factors and individual characteristics. RESULTS: The analysis included 977 patients. Altogether, 141 workers (14.4%) reported that they had experienced neck pain at least once during the 3-year follow-up period. The relation of neck pain to high quantitative job demands (relative risk [RR], 2.14; 95% confidence interval [CI], 1.28-3.58) and low coworker support (RR, 2.43; 95% CI, 1.11-5.29) was statistically significant. An increased risk was found for low decision authority in relation to neck pain (RR, 1.60; 95% CI, 0.74-3.45), but this relation was not statistically significant. CONCLUSIONS: High quantitative job demands and low coworker support are independent risk factors for neck pain. There are indications that another risk factor for neck pain is low decision authority.

Psychosocial work characteristics and psychological strain in relation to low-back pain.

OBJECTIVES: This study investigated the relationship between psychosocial work characteristics and low-back pain and the potential intermediate role of psychological strain variables in this relationship. METHODS: The research was part of a prospective cohort study of risk factors for musculoskeletal symptoms. The study population consisted of 861 workers from 34 companies in The Netherlands who had no low-back pain at baseline and for whom data on the occurrence of low-back pain were obtained with annual questionnaires during a 3-year follow-up period. Information on psychosocial work characteristics and psychological strain variables was collected using a questionnaire at baseline. Cases of low-back pain were defined as workers who reported, in at least one of the annual follow-up questionnaires, that they had had regular or prolonged low-back pain in the previous 12 months. RESULTS: After adjustment for individual factors and quantified physical load at work, nonsignificant relative risks ranging from 1.3 to 1.6 were observed for high quantitative job demands, high conflicting demands, low supervisory support, and low co-worker support. Decision authority and skill discretion showed no relationship with low-back pain. In general, the estimated relative risks for the psychosocial work characteristics were scarcely influenced by additional adjustment for job satisfaction, emotional exhaustion, and sleeping difficulties. CONCLUSIONS: It can be concluded that low social support, from either supervisors or co-workers, appears to be a risk factor for low-back pain. Some indications of a relationship between high quantitative job demands and high conflicting demands and low-back pain were also found. Little evidence was found for an intermediate role for the psychological strain variables under study.

Are neck flexion, neck rotation, and sitting at work risk factors for neck pain? Results of a prospective cohort study.

OBJECTIVE: To study the relation between neck pain and work related neck flexion, neck rotation, and sitting. METHODS: A prospective cohort study was performed with a follow up of 3 years among 1334 workers from 34 companies. Work related physical load was assessed by analysing objectively measured exposure data (video recordings) of neck flexion, neck rotation, and sitting posture. Neck pain was assessed by a questionnaire. Adjustments were made for various physical factors that were related or not related to work, psychosocial factors, and individual characteristics. RESULTS: A significant positive relation was found between the percentage of the working time in a sitting position and neck pain, implying an increased risk of neck pain for workers who were sitting for more than 95% of the working time (crude relative risk (RR) 2.01, 95% confidence interval (95% CI) 1.04 to 3.88; adjusted RR 2.34, 95% CI 1.05 to 5.21). A trend for a positive relation between neck flexion and neck pain was found, suggesting an increased risk of neck pain for people working with the neck at a minimum of 20 degrees of flexion for more than 70% of the working time (crude RR 2.01, 95% CI 0.98 to 4.11; adjusted RR 1.63, 95% CI 0.70 to 3.82). No clear relation was found between neck rotation and neck pain. CONCLUSION: Sitting at work for more than 95% of the working time seems to be a risk factor for neck pain and there is a trend for a positive relation between neck flexion and neck pain. No clear relation was found between neck rotation and neck pain.

Psychosocial risk factors for neck pain: a systematic review.

BACKGROUND: Neck pain, which is assumed to be a multifactorial disease, is a major problem in modern society. METHODS: To identify the most important psychosocial risk factors for neck pain, a systematic review of the literature was carried out. The methodological quality of all studies in the review was assessed. Four levels of evidence were defined to assess the strength of evidence for potential risk factors for neck pain (strong, moderate, some or inconclusive evidence). RESULTS: Some evidence was found for a positive relationship between neck pain and high quantitative job demands, low social (coworker) support, low job control, high and low skill discretion and low job satisfaction. Inconclusive evidence was found for high job strain, low supervisor support, conflicts at work, low job security, and limited rest break opportunities. CONCLUSIONS: The procedure of the assessment of the methodological quality and the rating system applied to distinguish between high- and low-score studies, had a considerable influence on the level of evidence, indicating that changes in this procedure may have a major impact on the overall conclusions of this review.

Physical risk factors for neck pain.

To identify physical risk factors for neck pain, a systematic review of the literature was carried out. Based on methodological quality and study design, 4 levels of evidence were defined to establish the strength of evidence for the relationship between risk factors and neck pain. Altogether, 22 cross-sectional studies, 2 prospective cohort studies, and 1 case-referent study were eligible for determining the level of evidence. The results showed some evidence for a positive relationship between neck pain and the duration of sitting and twisting or bending of the trunk. A sensitivity analysis was carried out excluding 3 items of the quality list, the importance of which seemed doubtful. On the basis of this sensitivity analysis, it was concluded that there is some evidence for a positive relationship between neck pain and the following work-related risk factors: neck flexion, arm force, arm posture, duration of sitting, twisting or bending of the trunk, hand-arm vibration, and workplace design.

Flexion and rotation of the trunk and lifting at work are risk factors for low back pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among workers of 34 companies in the Netherlands. OBJECTIVES: To investigate the relation between flexion and rotation of the trunk and lifting at work and the occurrence of low back pain. SUMMARY OF BACKGROUND DATA: Previous studies on work-related physical risk factors for low back pain either lacked quantification of the physical load or did not take confounding by individual and psychosocial factors into account. METHODS: The study population consisted of 861 workers with no low back pain at baseline and complete data on the occurrence of low back pain during the 3-year follow-up period. Physical load at work was assessed by means of analyses of video-recordings. Information on other risk factors and the occurrence of low back pain was obtained by means of self-administered questionnaires. RESULTS: An increased risk of low back pain was observed for workers who worked with the trunk in a minimum of 60 degrees of flexion for more than 5% of the working time (RR 1.5, 95% CI 1.0-2.1), for workers who worked with the trunk in a minimum of 30 degrees of rotation for more than 10% of the working time (RR 1.3, 95% CI 0.9-1. 9), and for workers who lifted a load of at least 25 kg more than 15 times per working day (RR 1.6, 95% CI 1.1-2.3). CONCLUSIONS: Flexion and rotation of the trunk and lifting at work are moderate risk factors for low back pain, especially at greater levels of exposure.

The longitudinal development of running economy in males and females aged between 13 and 27 years: the Amsterdam Growth and Health Study.

The purpose of this study was to describe the longitudinal development of running economy [defined as the oxygen uptake (VO2) at a submaximal running speed] in males and females from teenage to young adult age using data from the Amsterdam Growth and Health Study. Submaximal VO2 (in ml.kg-1.min-1) was measured in 84 males and 98 females while they ran on a treadmill at a constant speed of 8 km.h-1 for 6 min at three different treadmill slopes (0%, 2.5% and 5%). This test was carried out six times, on the same subjects at the ages of 13, 14, 15, 16, 21, and 27 years. The longitudinal development of running economy in males and females was analysed using a two-way analysis of variance for repeated measurements. At all three slopes, a significant decrease in VO2 with increasing age was found for both males and females, implying a significant increase in running economy for both sexes. Males showed significantly higher VO2 values than females at all ages measured and for all three slopes, suggesting that females have a significantly higher running economy than males. In order to make a better comparison of the VO2 of individuals of different sizes, allometric models were used; power function ratios were constructed in which body mass was expressed to an exponential power. Following this analysis the difference in submaximal VO2 and running economy between males and females appeared even larger.

Physical strain and mechanical efficiency in hubcrank and handrim wheelchair propulsion.

The physical strain and mechanical efficiency of manual wheelchair propulsion using handrim and hubcrank propelled racing wheelchairs were studied during a submaximal wheelchair exercise test on a stationary roller ergometer. Ten healthy male able-bodied subjects conducted two exercise tests in a random order and measurements of phyical strain (oxygen uptake, minute ventilation, respiratory exchange ratio, heart rate) and gross mechanical efficiency were obtained. During the experiment torque data, speed and power output were determined at a sample frequency of 0.1 Hz. Analysis of variance for repeated measures (p < 0.05) was used to establish differences. The hubcrank propulsion mechanism showed a significantly lower physical strain and higher gross mechanical efficiency in comparison with the handrim propulsion mechanism. The lower strain and higher efficiency in propelling the hubcrank partly seems to be due to the continuous biphasic cyclic propulsion movement, which allows both push and pull forces to be exerted. This involves flexor and extensor muscles around elbow and shoulder, leading to a reduced tendency to fatigue in individual muscles in the upper extremity. The more natural and neutral wrist-hand orientation also seems to diminish finger flexor activity and wrist-stabilizing muscle activity, and will thus reduce physical strain both with respect to the cardiorespiratory and musculoskeletal systems. The latter may influence the tendency to develop carpal tunnel problems positively. The reduced strain of the hubcrank propulsion mechanism clearly has a number of advantages over handrims for the human engine in the short and long run. However, technical innovation should address current practical problems of steering and braking. Clearly, hubcranks can be used in low-seated wheelchairs (i.e. racing wheelchairs) only, and in subjects with a sufficiently large range of motion in the upper extremity. Moreover, the increased width is a drawback of hubcranks. Care should be taken while negotiating door posts.