Workers' health surveillance targeting mental health: evaluation of a training.

BACKGROUND: Mental health complaints occur frequently among healthcare workers. A workers' health surveillance mental health module (WHS-MH) was found to be effective in improving work functioning of nurses, although not implemented regularly. Therefore, training for occupational physicians and nurses to facilitate the implementation of WHS-MH was developed and evaluated. AIMS: This study was aimed to evaluate the effect of training on knowledge, self-efficacy and motivation to implement WHS-MH, and to evaluate participants' satisfaction with the training. METHODS: Three-hour training was held among 49 occupational physicians and nurses in the Netherlands. Effect on knowledge, self-efficacy and motivation was assessed using knowledge tests and questionnaires before and immediately after the training. Satisfaction with the training was measured using questionnaires after the training. RESULTS: A mean knowledge test score of 5.3 (SD = 1.6) was found before training, which did not significantly increase after training (M = 5.6, SD = 1.8). In total, 43% agreed or strongly agreed to have sufficient skills to implement WHS-MH, which significantly increased to 78% after the training. Furthermore, 87% agreed or strongly agreed to be motivated to initiate WHS, which significantly increased to 94% after the training. The majority of participants were satisfied with the training. CONCLUSIONS: Training may enhance the implementation of the WHS-MH through increasing self-efficacy and motivation. However, no effect on level of knowledge to implement WHS-MH was found.

Work ability and percentage of hours worked related to limitations in patients with upper extremity musculoskeletal disorders: a cross-sectional cohort study.

BACKGROUND: The aim of this study was to assess the relationship between self-reported work ability and hours worked at the current time in Upper Extremity Musculoskeletal Disorders (UEMSD) patients. To further investigate this relationship, the association of work ability and working hours with several limitations in daily and working life were explored. METHODS: In this cross-sectional cohort study, a questionnaire was sent out to members of the UEMSD patient organisation, containing self-reported work ability, questions on working hours and limitations in work due to UEMSD. Limitations were measured with the Disabilities of Arm Shoulder and Hand questionnaire, ShortForm-36 subscales, and common hand grasps or grips. Work ability was measured with the work ability score, while worked hours were operationalised as the percentage of hours worked compared to fulltime. The correlation between worked hours and work ability was tested with the Pearson correlation coefficient. Variance in work ability and the hours worked were explained by limitations and assessed with two linear regression analyses. RESULTS: Based on data of 794 respondents a moderate correlation was found between work ability and worked hours r = 0.46; 95% CI [0.40, 0.53]. Models including limitations explained 52 and 21% of total variance in work ability and worked hours, respectively. Variance in both can be explained by the degree of difficulties performing daily activities at work, limitations in daily activities as a consequence of health issues and the ability to perform a precision grip. Additionally, work ability can be explained by limitations at work and other daily activities due to physical health issues, while the percentage of hours can additionally be explained by the ability to grasp a large object with one hand, the ability to use a keyboard, and the subject's gender. CONCLUSIONS: The number of worked hours does not fully match the work ability. Although they share three predictors, work ability and worked hours seem to be based on different aspects. Compared to work hours, work ability is more strongly related to limitations in daily activities and work. Taking self-reported work ability into account can improve the fit between work limitations and work hours.

Work ability and work functioning: measuring change in individuals recently returned to work.

PURPOSE: To assess: (1) whether work ability and work-functioning instruments can detect relevant changes in their respective parameters following a return to work (RTW) and (2) what proportion of those returning to work show changes in their work ability and work functioning. METHODS: A total of 1073 workers who returned to work after at least 2 weeks of sick leave were invited to fill out three questionnaires in the first 8 weeks after RTW. These consisted of an appraisal of general, physical, and mental/emotional work ability (scores 0-10) and a work-functioning questionnaire (scores 0-100). Minimal Important Change (MIC) was defined to determine the proportion of people, whose scores had changed at weeks 5 and 8 following RTW. The Smallest Detectable Change (SDC) was determined to put the MIC in perspective of measurement error. RESULTS: Of all participants, 235 were eligible for the analysis. All MIC values were below the SDC and thus not suitable for use. The SDC for work ability was 2.2 and 19.9 for work functioning. In the first 5 weeks after RTW, 10-15% showed a relevant, measurable improvement in work ability, and work functioning based on the SDC margins. CONCLUSIONS: Both instruments were unable to identify change after RTW adequately. We can conclude that 10-15% of individuals showed improvement in work ability and work functioning in the first 5 weeks after RTW when SDC is used.

Reproducibility of work ability and work functioning instruments.

Background: Work ability (WA) and work functioning (WF) instruments can be useful in occupational health practice. The reproducibility of both instruments is important to their relevance for daily practice. Clinimetrics concerns the methodological and statistical quality of instruments and their performance in practice. Aims: To assess the reproducibility of WA and WF instruments. Methods: Dutch workers completed a questionnaire containing WA questions and the WF questionnaire twice with a 7-day interval between. The questionnaire included an appraisal of current general, physical and mental/emotional WA (0-10) and the composite WF questionnaire of 49 items (0-100). We measured reproducibility, reliability and agreement by calculating the intraclass correlation coefficient (ICC), the standard error of measurement (SEM) and the smallest detectable change (SDC). Results: The answers of 104 respondents were available for analysis. General, physical and mental/emotional WA had ICC values of 0.52, 0.69 and 0.56, respectively. For WF, the ICC value was 0.85. For general WA, the SEM was 0.71. For physical and mental/emotional WA, the SEMs were 0.75 and 0.74, respectively. For general, physical and mental/emotional WA, the SDC was 1.98, 2.09 and 2.05 respectively. The SEM of the WF score was 4.78, and the SDC was 13.25. Conclusions: The WA questions showed moderate reliability, while the WF instrument showed good reliability. Occupational health professionals can use the SDCs of the instruments to monitor changes in WA and WF in workers over time.

External Validation and Update of a Prediction Rule for the Duration of Sickness Absence Due to Common Mental Disorders.

Purpose The objective of the present study was to validate an existing prediction rule (including age, education, depressive/anxiety symptoms, and recovery expectations) for predictions of the duration of sickness absence due to common mental disorders (CMDs) and investigate the added value of work-related factors. Methods A prospective cohort study including 596 employees who reported sick with CMDs in the period from September 2013 to April 2014. Work-related factors were measured at baseline with the Questionnaire on the Experience and Evaluation of Work. During 1-year follow-up, sickness absence data were retrieved from an occupational health register. The outcome variables of the study were sickness absence (no = 0, yes = 1) at 3 and 6 months after reporting sick with CMDs. Discrimination between workers with and without sickness absence was investigated at 3 and 6 months with the area under the receiver operating characteristic curve (AUC). Results A total of 220 (37 %) employees agreed to participate and 211 (35 %) had complete data for analysis. Discrimination was poor with AUC = 0.69 and AUC = 0.55 at 3 and 6 months, respectively. When 'variety in work' was added as predictor variable, discrimination between employees with and without CMD sickness absence improved to AUC = 0.74 (at 3 months) and AUC = 0.62 (at 6 months). Conclusions The original prediction rule poorly predicted CMD sickness absence duration. After adding 'variety in work', the prediction rule discriminated between employees with and without CMD sickness absence 3 months after reporting sick. This new prediction rule remains to be validated in other populations.

Common mental disorders related to incidents and behaviour in physicians.

BACKGROUND: Common mental disorders (CMD-burnout, stress, depression and anxiety disorders) are prevalent in physicians. AIMS: To investigate the relationship between CMD and medical incidents and/or unprofessional behaviour in hospital physicians. METHODS: PubMed was searched for all articles published between 2003 and 2013 that study a relationship between CMD and medical incidents and/or unprofessional behaviour in hospital physicians. The strength of evidence was assessed through five levels of evidence. RESULTS: We included 15 studies. We found strong evidence for a significant association between burnout and the occurrence of medical incidents, based on two longitudinal and seven cross-sectional studies with a positive association [odds ratio (OR) 1.07-5.5]; one longitudinal study found a non-significant association (strong evidence). For the association between depression and medical incidents, four longitudinal studies and three cross-sectional studies found a significant positive association (strong evidence; OR 2.21-3.29). For the association between fatigue and medical incidents, one longitudinal study and one cross-sectional study showed a significant positive association, but one cross-sectional study showed a non-significant association (strong evidence; OR 1.37). For the association between sleepiness and medical incidents, one longitudinal study and two cross-sectional studies showed a significant positive association (strong evidence; OR 1.10-1.37). No significant association was found between burnout and unprofessional behaviour (inconsistent evidence). Nor was any evidence found for the association between unprofessional behaviour and depression, fatigue or sleepiness. CONCLUSIONS: CMD in hospital physicians were associated with the occurrence of self-reported medical incidents, but there was inconsistent evidence for unprofessional behaviour.

Development of hospital nurses' work ability over a 2 year period.

BACKGROUND: A new approach to the study of work ability is an individually oriented approach. This approach increases our understanding of how work ability develops over time among individuals with a different level of work ability. AIMS: To increase knowledge about individuals' work ability trajectories by studying hospital nurses' development of work ability over a 2 year period and factors associated with these trajectories. METHODS: We used a data set of a prospective cohort study of hospital nurses, which was surveyed for 2 years by means of three questionnaires on work characteristics, health and work ability. The outcome variable was the general work ability trajectory over the course of 2 years (favourable/unfavourable). The predictors were the individual, physical and mental work ability and health characteristics at baseline. A multivariate backwards stepwise logistic regression analysis was used. RESULTS: Of 572 nurses in the cohort, nearly one-third (31%, 179/572) showed an unfavourable general work ability trajectory. Low physical work ability (odds ratio (OR) 1.82; 95% confidence interval (95% CI) 1.12-2.95) and high level of fatigue (OR 1.52; 95% CI 0.97-2.40) at baseline were predictors for the unfavourable course of self-reported general work ability. CONCLUSIONS: A substantial proportion of this cohort of hospital nurses experienced a reduction in work ability over the course of 2 years. Baseline physical work ability and level of fatigue were related to this. The next step is to address these factors when counselling nurses and evaluate the effect of interventions aimed at improving physical work ability and reducing fatigue.

Predicting improvement of functioning in disability claimants.

PURPOSE: In the Netherlands, disability claimants are assessed after 2 years of sick leave, but their functioning may still improve. An accurate prognosis of functioning is difficult. Self predictions may be more accurate than those of professionals. The aim of this study, is to assess and compare the accuracy of predictions by disability claimants and insurance physicians (IPs) working at the Social Security Institute. It is further studied whether the accuracy differs between subgroups of claimants with mental or somatic health conditions. METHODS: We used data from the prospective cohort study cohort study. Following the assessment of the disability claim (n = 375) and after 1 year follow up (T1, n = 276) data on functioning were obtained from respondents by self-report questionnaire World Health Organization Disability Schedule 2.0. Both claimants and IPs were asked to predict improvement of functioning. Accuracy of their predictions were assessed by sensitivity, specificity, and area under the receiver operating curves (AUC). Mixed logistic regression was conducted to explore differences in accuracy between claimants with mental and somatic conditions. RESULTS: One-third (32 %) of disability claimants improved beyond the standard error of measurement. Disability claimants' and IPs were able to predict this improvement of functioning, but to a limited extent, with an AUC of 0.61 for IPs and 0.62 for disability claimants. We found no statistically significant differences in the accuracy of the predictions in claimants with mental or somatic health conditions. CONCLUSIONS: Improvements of functioning were not uncommon. However, both IPs and disability claimants were unable to predict improvement with high levels of accuracy in both mental and somatic health conditions.

Impaired work functioning due to common mental disorders in nurses and allied health professionals: the Nurses Work Functioning Questionnaire.

PURPOSE: Common mental disorders (CMD) negatively affect work functioning. In the health service sector not only the prevalence of CMDs is high, but work functioning problems are associated with a risk of serious consequences for patients and healthcare providers. If work functioning problems due to CMDs are detected early, timely help can be provided. Therefore, the aim of this study is to develop a detection questionnaire for impaired work functioning due to CMDs in nurses and allied health professionals working in hospitals. METHODS: First, an item pool was developed by a systematic literature study and five focus group interviews with employees and experts. To evaluate the content validity, additional interviews were held. Second, a cross-sectional assessment of the item pool in 314 nurses and allied health professionals was used for item selection and for identification and corroboration of subscales by explorative and confirmatory factor analysis. RESULTS: The study results in the Nurses Work Functioning Questionnaire (NWFQ), a 50-item self-report questionnaire consisting of seven subscales: cognitive aspects of task execution, impaired decision making, causing incidents at work, avoidance behavior, conflicts and irritations with colleagues, impaired contact with patients and their family, and lack of energy and motivation. The questionnaire has a proven high content validity. All subscales have good or acceptable internal consistency. CONCLUSION: The Nurses Work Functioning Questionnaire gives insight into precise and concrete aspects of impaired work functioning of nurses and allied health professionals. The scores can be used as a starting point for purposeful interventions.

Psychosocial work environment and stress-related disorders, a systematic review.

BACKGROUND: Knowledge on the impact of the psychosocial work environment on the occurrence of stress-related disorders (SRDs) can assist occupational physicians in the assessment of the work-relatedness of these disorders. AIMS: To systematically review the contribution of work-related psychosocial risk factors to SRDs. METHODS: A systematic review of the literature was carried out by searching Medline, PsycINFO and Embase for studies published up until October 2008. Studies eligible for inclusion were prospective cohort studies or patient-control studies of workers at risk for SRDs. Studies were included in the review when data on the association between exposure to psychosocial work factors and the occurrence of SRDs were presented. Where possible, meta-analysis was conducted to obtain summary odds ratios of the association. The strength of the evidence was assessed using four levels of evidence. RESULTS: From the 2426 studies identified, seven prospective studies were included in this review. Strong evidence was found that high job demands, low job control, low co-worker support, low supervisor support, low procedural justice, low relational justice and a high effort-reward imbalance predicted the incidence of SRDs. CONCLUSIONS: This systematic review points to the potential of preventing SRDs by improving the psychosocial work environment. However, more prospective studies are needed on the remaining factors, exposure assessment and the relative contributions of single factors, in order to enable consistent assessment of the work-relatedness of SRDs by occupational physicians.

Factors associated with work participation and work functioning in depressed workers: a systematic review.

BACKGROUND: Depression is associated with negative work outcomes such as reduced work participation (WP) (e.g., sick leave duration, work status) and work functioning (WF) (e.g., loss of productivity, work limitations). For the development of evidence-based interventions to improve these work outcomes, factors predicting WP and WF have to be identified. METHODS: This paper presents a systematic literature review of studies identifying factors associated with WP and WF of currently depressed workers. RESULTS: A total of 30 studies were found that addressed factors associated with WP (N = 19) or WF (N = 11). For both outcomes, studies reported most often on the relationship with disorder-related factors, whereas personal factors and work-related factors were less frequently addressed. For WP, the following relationships were supported: strong evidence was found for the association between a long duration of the depressive episode and work disability. Moderate evidence was found for the associations between more severe types of depressive disorder, presence of co-morbid mental or physical disorders, older age, a history of previous sick leave, and work disability. For WF, severe depressive symptoms were associated with work limitations, and clinical improvement was related to work productivity (moderate evidence). Due to the cross-sectional nature of about half of the studies, only few true prospective associations could be identified. CONCLUSION: Our study identifies gaps in knowledge regarding factors predictive of WP and WF in depressed workers and can be used for the design of future research and evidence-based interventions. We recommend undertaking more longitudinal studies to identify modifiable factors predictive of WP and WF, especially work-related and personal factors.

Interventions to improve occupational health in depressed people.

BACKGROUND: Work disability such as sickness absence is common in people with depression. OBJECTIVES: To evaluate the effectiveness of interventions aimed at reducing work disability in depressed workers. SEARCH STRATEGY: We searched the CCDANCTR-Studies and CCDANCTR-References on 2/8/2006, Cochrane Library CENTRAL register, MEDLINE, EMBASE, CINAHL, PsycINFO, OSH-ROM (Occupational Safety and Health), NHS-EED, and DARE. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and cluster RCTs of work-directed and worker-directed interventions for depressed people, using sickness absence as the primary outcome DATA COLLECTION AND ANALYSIS: Two authors independently extracted data and assessed trial quality. We used standardised mean differences (SMD) with 95% confidence intervals (CIs) to pool study results where possible. MAIN RESULTS: We included eleven studies, all of worker-directed interventions, involving 2556 participants. Only one study addressed work issues using adjuvant occupational therapy. Other interventions evaluated anti-depressant medication (selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, monoamino-oxidase inhibitors), psychodynamic therapy, enhanced primary care and psychological treatment. For medication, the combined results of three studies (n=864) showed no difference between antidepressant medication and alternative medication in their effect on days of sickness absence (SMD 0.09; 95% CI -0.05 to 0.23) In two pooled studies (n=969), the effect of enhanced primary care on days of sickness absence did not differ from usual care in the medium term (SMD -0.02; 95% CI -0.15 to 0.12). All other comparisons were based on single studies (n=6), all of which showed a lack of significant difference for sickness absence between groups, with the exception of one small study, combined psychodynamic therapy and TCAs versus TCAs alone, which favoured the combined treatment. AUTHORS' CONCLUSIONS: Based on a heterogeneous sample of studies, there is currently no evidence of an effect of medication alone, enhanced primary care, psychological interventions or the combination of those with medication on sickness absence of depressed workers. In future RCTs, interventions should specifically address work issues, and occupational outcomes should be used to measure the effect..

Supervisory behaviour as a predictor of return to work in employees absent from work due to mental health problems.

AIMS: To study supervisory behaviour as a predictive factor for return to work of employees absent due to mental health problems; and to explore the association between conditional factors and supervisory behaviour. METHODS: Eighty five supervisors of employees were interviewed by telephone. Questionnaires providing information on person related factors, depressive symptoms, and sickness absence were sent to the employees at baseline, three months, six months, and after one year. Three aspects of supervisory behaviour during the period of absence were measured: communication with the employee, promoting gradual return to work, and consulting of other professionals. RESULTS: Better communication between supervisor and employee was associated with time to full return to work in non-depressed employees. For employees with a high level of depressive symptoms, this association could not be established. Consulting other professionals more often was associated with a longer duration of the sickness absence for both full and partial return to work. If sickness absence had financial consequences for the department, the supervisor was more likely to communicate frequently with the employee. Supervisors who were responsible for return to work in their organisation were more likely to communicate better and to consult more often with other professionals. CONCLUSION: Supervisors should communicate more frequently with employees during sickness absence as well as hold follow up meetings more often as this is associated with a faster return to work in those employees.

Quality of rehabilitation among workers with adjustment disorders according to practice guidelines; a retrospective cohort study.

AIMS: To assess the quality of occupational rehabilitation for patients with adjustment disorders and to determine whether high quality of care is related to a shorter period of sickness absence. METHODS: A retrospective cohort study was conducted by means of an audit of 100 files of patients with adjustment disorders who visited their occupational physicians. Quality of rehabilitation was assessed by means of 10 performance indicators, derived from the guidelines for the treatment of employees with mental health disorders. Performance was dichotomised into optimal and deviant care according to explicit criteria. The performance rates were related to time until work resumption during a one year follow up period. Kaplan-Meier survival analyses and Cox proportional hazards analysis were used to study this relation. RESULTS: Four of 10 performance rates were below 50%: continuity of care (34%), interventions aimed at providers of care in the curative sector (39%), assessment of impediments in the return to work process (41%), and assessment of symptoms (45%). The highest performance rate concerned assessment of work related causes (94%). Overall optimal care was found in 10% of the cases. Median time to complete recovery was 195 days (IQR 97 to 365), and 73% of all patients recovered completely after one year. Optimal continuity of care was significantly related to a shorter time to both partial and complete work resumption (hazard ratio (HR) 0.3; CI 0.2 to 0.6) independently of other performance indicators. Performance regarding interventions aimed at the organisation was also related to a shorter time until first return to work (HR 0.5; CI 0.3 to 0.9). CONCLUSIONS: This study shows that the rehabilitation process of employees with adjustment disorders leaves significant room for improvement, especially with regard to continuity of care. Quality of care was partly related to a better outcome. More rigorous study designs are needed to corroborate these findings.

The Depression Anxiety Stress Scales (DASS): detecting anxiety disorder and depression in employees absent from work because of mental health problems.

AIMS: To (1) evaluate the psychometric properties and (2) examine the ability to detect cases with anxiety disorder and depression in a population of employees absent from work because of mental health problems. METHODS: Internal consistency, construct validity, and criterion validity of the Depression Anxiety Stress Scales (DASS) were assessed. Furthermore, the ability to identify anxiety disorders or depression was evaluated by calculating posterior probabilities of these disorders following positive and negative test results for different cut off scores of the DASS-Depression and DASS-Anxiety subscales. RESULTS: Internal consistency of the DASS subscales was high, with Cronbach's alphas of 0.94, 0.88, and 0.93 for depression, anxiety, and stress respectively. Factor analysis revealed a three factor solution, which corresponded well with the three subscales of the DASS. Construct validity was further supported by moderately high correlations of the DASS with indices of convergent validity (0.65 and 0.75), and lower correlations of the DASS with indices of divergent validity (range -0.22 to 0.07). Support for criterion validity was provided by a statistically significant difference in DASS scores between two diagnostic groups. A cut off score of 5 for anxiety and 12 for depression is recommended. The DASS showed probabilities of anxiety and depression after a negative test result of 0.05 and 0.06 respectively. Probabilities of 0.29 for anxiety disorder and 0.33 for depression after a positive test result reflect relatively low specificity of the DASS. CONCLUSION: The psychometric properties of the DASS are suitable for use in an occupational health care setting. The DASS can be helpful in ruling out anxiety disorder and depression in employees with mental health problems.

Fetal gender and aggression in pregnant stumptail monkeys (Macaca arctoides).

Agonistic behaviors of pregnant female stumptail monkeys, members of a large, well-integrated group continuously living together, were studied during 480 observation hours (over 32 months). A total of 28 pregnancies of 20 females occurred, resulting in 12 male and 16 female live infants. The main finding was a significant decline in aggression, both received and performed, during the course of pregnancy. There was no clear unequivocal effect of fetal gender on aggressive behavior of the mothers-to-be.

Behavioral aspects of puberty in group-living stumptail monkeys (Macaca arctoides).

Behavioral changes before and around the time of puberty were studied in a longitudinal manner in male and female stumptail monkeys. Around the time of testicular descent (mean age: 3.3 years) males started to become more aggressive towards adult males. Within two years following testicular descent males rose in rank with the support of others and reached stable (sub)top positions in the dominance hierarchy. In the female rank-stabilization took place gradually between one year before and two years after first ovulation (mean age: 3.7 years). Copulatory activity began about two (in females) to two-and-a-half years (in males) before reproductive capacity was attained. Female copulatory activity began to rise about six months before first ovulation, when they started to copulate with adult males. In males copulatory frequency rose sharply between six and twelve months prior to testicular descent. Until a few months after testicular descent males could copulate openly in the group without interruption; from about 1 year following testicular descent virtually all copulations had to take place surreptitiously to avoid interruption by higher ranking adult males. It is postulated that this decreasing tolerance of adults may contribute to the process of peripheralization and migration of young adult males which occur in free ranging macaque groups.

Testosterone, testis size, seasonality, and behavior in group-living stumptail macaques (Macaca arctoides).

During a 28-month period, data were collected on physiological parameters and sociosexual behavior of 13 adult male members of a large mixed-sex group of stumptail macaques living in an outdoor cage. Monthly measurements of plasma testosterone, testis size, and body weight revealed no systematic seasonality. Seasonal variations did occur in branch shaking and grooming (both with low rates in winter), but not in other behaviors studied (copulation, masturbation, aggression). Dominance ranks were stable throughout the study period and were not significantly correlated with mean testosterone levels. Temporal fluctuations in behavioral frequencies did not parallel testosterone fluctuations. Interindividual differences in behavioral frequencies were often correlated with dominance rank, but not with testosterone levels.

Physiological aspects of puberty in group-living stumptail monkeys (Macaca arctoides).

Physiological changes around the time of puberty were studied in a longitudinal manner in male and female stumptail macaques. In the male, testicular descent (mean age 3.3 years) is an early sign of puberty, which coincides with onset of the pubertal spurt in body weight and testis growth and precedes the pubertal rise in plasma testosterone. In the female no clear external signs of puberty have been found. Measurements of plasma progesterone yielded proof of first ovulation (mean age 3.7 years), a late sign of puberty in primates. This event coincided with a fall in the rate of body weight growth at the end of the pubertal growth spurt. Reproductive capacity of both males (first ejaculation) and females (first conception) appears to be reached around the 4th birthday.

Blood variables in adult stumptail macaques (Macaca arctoides) living in a captive group; annual variability.

Monthly blood samples were collected for more than two years from adult stumptail macaques living in a large captive group. The social organization, feeding pattern, and food composition were stable throughout the study period. No seasonal variability was observed for any of the 30 blood variables studied. It appeared that for each variable, within-animal variance was small relative to between-animal variance. A table of means and reference ranges is presented and discussed.