From Confounders to Suspected Risk: The Role of Psychosocial Factors Michael Feuerstein, Ph.D., MPH

Transcription

1 From Confounders to Suspected Risk: The Role of Psychosocial Factors Michael Feuerstein, Ph.D., MPH Uniformed Services University of the Health Sciences Bethesda, Maryland

2 McGorry et al., STAR Symposium

3 McGorry et al., STAR Symposium

4 McGorry et al., STAR Symposium

5 The Workplace External Loads The Person Biomechanical Loading Internal Loads Physiological Responses Organizational Factors Internal Tolerances Mechanical Strain Fatigue Individual Factors Social Context Outcomes Pain Discomfort Impairment Disability NRC, 2001

6 The Workplace External Loads The Person Biomechanical Loading Internal Loads Physiological Responses Organizational Factors Individual Factors Internal Tolerances Mechanical Strain Fatigue Social Context Outcomes Pain Discomfort Impairment Disability NRC, 2001

7 2003 STAR Symposium Criteria for Evaluating the Validity of a Suspected Risk Factor Strength-the value of the OR or RR Consistency-association repeatedly observed Specificity-association limited to a particular type of exposure and specific disease Temporal relationship-confidence of suspected cause preceded the observed effect Dose response-increasing risk with increasing dose Plausibility-is suggestion of causality biologically plausible Coherence-suggestion of causality conflict with other known data on natural history and etiology of disease Experimental confirmation-effect of intervention

8 ERGONOMIC RISK ESTIMATES: UPPER EXTREMITY DISORDERS 2003 STAR Symposium Null Association Positive Association n Range n Range Repetition Force Repetition & Force Repetition & Cold Vibration Source: NRC, 2001

9 ERGONOMIC RISK ESTIMATES: BACK DISORDERS 2003 STAR Symposium Null Association Positive Association n Range n Range Manual material handling Frequent bending & twisting Heavy physical load Static work posture Repetitive movements Whole-body vibration Source: NRC, 2001

10 Individual Psychosocial Factors and Back Pain: 38 Prospective Studies Null Association Positive Association Attributable Fraction (%) Individual Psychosocial Factors n n n Range Depression or anxiety a Psychological distress b Personality factors Fear-avoidance-coping Pain behavior / function c a 17 studies assessed depression only, 2 anxiety studies only, and 3 studies both depression and anxiety. b19 studies assessed psychological distress and 2 assessed stress. c 4 studies assessed pain behavior, and 3 assessed pain-related functioning. Source: NRC, STAR Symposium

11 Work Related Psychosocial Risk Factors and WRUEDs Null Association Positive Association Attributable Fraction (%) Work-Related Psychosocial Factors n Range n Range n Range High job demands Low decision latitude; low control and low stimulus from work Low social support Low job satisfaction High perceived job stress Few rest break opportunities Low support nonwork-related Worry, tension, psychological distress, nonwork-related Source: NRC, STAR Symposium

12 Work-Related Psychosocial Factors and Back Pain: 21 Prospective Studies Null Association Positive Association Attributable Fraction (%) Work-Related Psychosocial Factors n n n Range High job demands Low decision latitude/control 0 2 Low stimulus from work Low social support at work Low job satisfaction High perceived stress High perceived emotional effort 0 3 Perceived ability to return to work 0 3 Perceived work dangerous to back 0 2 Source: NRC, STAR Symposium

13 2003 STAR Symposium Risk Factors for WRUEDs Physical Heavy lifting Monotonous work tasks Static work postures Vibration Repetitive motion High work pace Poorly designed workplaces (ergonomics) Psychosocial Low social support High perceived workload Time pressure Low job control Perceived stress High psychological job demands Individual Physiology Perception Personality Coping mechanisms Behavior

14 Work Stressor Combinations Associated with Musculoskeletal Symptoms Upper Extremity Only Biomechanical Exposure & Time Pressure (OR = 3.0) Low Back Only Biomechanical Exposure & Time Pressure (OR = 2.7) Concurrent Low Back & Upper Extremity Biomechanical Exposure & Cognitive Demands (OR = 2.4) Cognitive Processing (OR = 2.1) Time Pressure (OR = 2.4) Participatory Mgmt (OR = 2.6) 2003 STAR Symposium

15 2003 STAR Symposium Bridging the Gap Workstyle May explain why individuals exposed to the same ergonomic stressors do not develop WRUEDs (Feuerstein, 1996) Description of how people perform work Individual pattern of cognitions, behaviors, and physiologic reactivity that co-occur while performing job tasks May be associated with alterations in physiologic state that, following repeated activation, can contribute to the development, exacerbation, and/or maintenance of chronic work-related musculoskeletal symptoms

16 2003 STAR Symposium Workstyle Definition Adverse workstyle may be elicited by high work demand (communicated or perceived), or self-generated by a high need for acceptance and achievement, fear of negative consequences, time pressure, or lack of awareness of the consequences of a particular workstyle

17 WORKSTYLE MODEL 2003 STAR Symposium WORKPLACE PSYCHOSOCIAL STRESSORS WORK DEMANDS Feuerstein, 1996; Feuerstein, Huang, Pransky, 1999 WORKSTYLE: Behavioral Cognitive Physiological ERGONOMIC STRESSORS UE SYMP- TOMS, 1999 W O R K UE DISORDERS D I S A B I L I T Y

18 2003 STAR Symposium Scale Development Preliminary studies support the workstyle concept and indicate that it needs further investigation Previous study resulted is a survey of 91 items that demonstrated good psychometric properties Present study addresses the need to develop a brief measure of the workstyle concept

19 2003 STAR Symposium Method Subjects/Recruitment Subjects recruited from Washington DC area through ads in local newspapers and flyers and by word-of-mouth Focus Groups (item generation) n=34 Baseline n=282 Retest n=144 Apparatus Subjects completed self-report measures online at

20 2003 STAR Symposium Measures Risk Job stress Ergonomic Risk Workstyle Items generated from a structured focus-groups (workers, health care providers and ergonomists) Outcome Symptoms/Pain Functional Limitation Physical and Mental Health Other Data (e.g., Demographic data; Social Desirability)

21 Sample Characteristics 2003 STAR Symposium No symptoms (n= 67) m SD Work-related symptoms (n= 141) m SD Non-workrelated symptoms (n=74) m SD Total (n= 282) m SD Age (in years) 40.4 (11.5) 40.4 (10.5) 42.7 (10.8) 41 (10.9) Years at Job 5.9 (6.8) 6.3 (6.5) 6.4 (6.8) 6.2 (6.6) Hours of Work per Week 42.5 (6.8) 42.8 (11.0) 40.0 (9.9) 42.3 (9.9) n % n % n % n % Gender Females Males 49 (73.1) 18 (26.9) 106 (75.2) 35 (24.8) 58 (78.4) 16 (21.6) 213 (75.5) 69 (24.5) Education H.S. Grad/GED Some College AA/Bachelor s Degree Some Graduate School Graduate Degree Marital Status Married Single Single (Cohabiting) Divorced Separated Widowed 3 (4.5) 15 (22.4) 21 (31.3) 5 (7.5) 23 (34.3) 31 (46.3) 26 (38.8) 0 (0.0) 6 (9.0) 2 (3.0) 2 (2.0) 7 (5.0) 42 (29.8) 35 (24.8) 19 (13.5) 38 (27.0) 64 (45.4) 37 (26.2) 12 (8.5) 19 (13.5) 5 (3.5) 4 (2.8) 5 (6.8) 21 (28.4) 17 (23.0) 5 (6.8) 26 (35.1) 25 (33.8) 24 (32.4) 11 (14.9) 12 (16.2) 1 (1.4) 1 (1.4) 15 (5.3) 78 (27.7) 73 (25.9) 29 (10.3) 87 (30.9) 120 (42.6) 87 (30.9) 23 (8.2) 37 (13.1) 8 (2.8) 7 (2.5)

22 The Workstyle Survey 2003 STAR Symposium Initial survey consisted of 10 factors with 91 items Initial Variance (%) Eigenvalue Working Through Pain Social Reactivity Limited Workplace Support Deadlines/Pressure Self-imposed Workpace/Workload Breaks Mood Pain/Tension Autonomic Response Numbness/Tingling

23 2003 STAR Symposium Internal Consistency of Workstyle Factors Workstyle Factor Chronbach s Alpha Working Through Pain Social Reactivity Limited Workplace Support Deadlines/Pressure Self-imposed Workpace/Workload Breaks Mood Pain/Tension Autonomic Numbness/Tingling

24 Test-Retest Reliability for Workstyle Scales Workstyle Scale Pearson Correlation Working Through Pain 0.834* Social Reactivity 0.815* Limited Workplace Support 0.800* Deadlines/Pressure 0.870* Self-imposed Workpace/Workload 0.799* Breaks 0.730* WS Part 1 Score - Characteristic Responses at Work (Cognitions/Behaviors) 0.887* Mood 0.758* Pain/Tension 0.745* Autonomic 0.684* Numbness/Tingling 0.773* WS Part 2a Score Physiological Response 0.791* WS Part 2b Score Symptom Response 0.816* WS Total Score 0.897* ** denotes correlation is significant at the 0.01 level STAR Symposium

25 Correlations 2003 STAR Symposium Total Workstyle Score r JRPD Ergo Risk.455 ** LSRES Job Stress.602 ** Quantitative workload.410 ** Workload Variance.455 ** Exhaustion.542 ** Skill Discretion.120 * Decision Authority ** Psych Workload.214 ** Social Desirability ** * p < 0.05 ** p < 0.01

26 2003 STAR Symposium The Workstyle Measure Initial survey consisted of 10 factors with 91 total items Moderate to high internal consistency among the subscales (alpha=0.61 to 0.91) Good test-retest reliability of the total score (r=0.90) Dose-response relationship between increasing total score and increasing levels of adverse health outcome measures. High workstyle scores associated with odds ratio of 2.5 for classification as case with WRUE symptoms

27 Prediction of Case Status Independent Variable (Range) OR (95% CI) B Job Stress NIOSH Job Stress Workload Variability (0-12) High (8-12) Exhaustion (0-8) High (3-8) Job Content Questionnaire Decision Authority (0-6) High (3-6) LSRES Job Stress (0-20) High (8-20) 0.91 ( ) 1.36 ( ) 0.42 ( ) 0.66 ( ) Individual Factors Marlowe-Crowne Social Desirability (0-13) High (9-13) 0.97 ( ) Ergonomic Risk Exposure JRPDS (0 60) High (26-60) Perceived Exertion (0-10) High (3-10) % Time at VDU (0%-100%) High (50%-100%) 2.60 ( )* 0.98 ( ) 1.96 ( )* Workstyle Total Workstyle Score (0-19.6) High ( ) 3.01 ( )* 1.10 *p<0.05

28 Short Form 2003 STAR Symposium

29 2003 STAR Symposium Scale Reduction Method Factor analyses on 91 workstyle items and exclusion of items with factor loading less than 0.5 Random split half selection of items within each subscale Pre-existing symptoms subscales excluded to reduce predictive bias

30 2003 STAR Symposium Psychometric Properties Internal consistency: α=0.89 Test-retest reliability: r=0.88* Correlation with complete Workstyle Survey: r=0.98* Linear trend analyses: significant linear trend for increasing adverse outcomes including pain (F=38.53*) and functional limitation (F=66.41*). *p<0.01

31 Concurrent Validity 2003 STAR Symposium Correlation to Total Workstyle Score r JRPD Ergo Risk 0.49** LSRES Job Stress 0.59** Quant workload 0.40** Workload variance 0.47** Exhaustion 0.54** Skill Discretion 0.10 Decision Authority -0.27** Psych workload 0.19** Social Desirability -0.27** **p<0.01

32 2003 STAR Symposium Dose-Response Relationship: Pain VAS Pain Rating Workstyle Score Quartile 1 Quartile 2 Quartile 3 Quartile 4

33 2003 STAR Symposium Dose-Response Relationship: Symptoms Symptom Scores Quartile 1 Quartile 2 Quartile 3 Quartile 4 0 Workstyle Score

34 2003 STAR Symposium Dose-Response Relationship: Functional Limitation UEFS Score Quartile 1 Quartile 2 Quartile 3 Quartile 4 Workstyle Score

35 2003 STAR Symposium Dose-Response Relationship: Physical Health SF-12 PCS Score Quartile 1 Quartile 2 Quartile 3 Quartile 4 42 Workstyle Score

36 2003 STAR Symposium Dose-Response Relationship: Mental Health SF-12 MCS Scores Workstyle Score Quartile 1 Quartile 2 Quartile 3 Quartile 4

37 2003 STAR Symposium e2.60 Work Load.77 e3.82 Work Load Variance.90 Work Demands.50 e9 e Characteristic Response To Work Response To Increased Work Demands Work Style Outcome.31 e14.17 JRPD.41 Ergo Stress Symptoms.10 e17

38 2003 STAR Symposium e2.59 Work Load Work Demands e3.82 Work Load Variance.50 e9 e8.92 Characteristic Response To Work Response To Increased Work Style 1.00 Outcome.44 Work Demands e14.17 JRPD.41 Ergo Stress Functional Limitation.14 e17

39 2003 STAR Symposium e2.59 Work Load Work Demands e3.82 Work Load Variance.50 Characteristic e9 Response To.92 Work.96 Response To.66 Work Style 1.00 Outcome e8 Increased.44 Work Demands e14.17 JRPD.41 Ergo Stress Pain.10 e17

40 WORKSTYLE MODEL 2003 STAR Symposium WORKPLACE PSYCHOSOCIAL STRESSORS WORK DEMANDS Feuerstein, 1996; Feuerstein, Huang, Pransky, 1999 WORKSTYLE: Behavioral Cognitive Physiological ERGONOMIC STRESSORS UE SYMP- TOMS, 1999 W O R K UE DISORDERS D I S A B I L I T Y

41 Workstyle Score Distribution 2003 STAR Symposium 40 ws cog/beh/phys 30 Frequency Std. Dev = Mean = 80.4 N = ws cog/beh/phys

42 2003 STAR Symposium Conclusions Innovative concepts and measures are emerging e.g., workstyle short form reliable (internal consistency/testretest) Discriminates symptomatic cases from controls Dose-response with pain, functional limitation, physical/mental health Laboratory-based & prospective studies needed to further validate the measure Future intervention efforts should consider high-risk workstyle

43 2003 STAR Symposium Candidate Polymorphisms for Workstyle Related Upper Extremity Pain 5HTT -serotonin transporter COMT -catechol-o-methyltransferase AR alpha A- alpha 2A adrenergic receptor gene TH- tyrosine hydroxylase Belfer et al, in press.