Occupational and non-occupational risk factors correlating with the severity of clinical manifestations of carpal tunnel syndrome and related work disability among workers who work with a computer

Çupi, Blerim; Šarac, Ivana; Jovanović, Jovana J.; Jovanović, Stefan; Petrović-Oggiano, Gordana; Debeljak-Martačić, Jasmina; Jovanović, Jovica

doi:10.2478/aiht-2023-74-3754

Figures & Tables

Participants’ data on occupational factors related and not related to computer-work

Variable	All (N=190)
Duration of occupational work with computer, months, median (IQR)	52.5 (27.8–150.0)
Average daily time spent in occupational work with computer, minutes, median (IQR)	240.0 (170.0–360.0)
Average daily time spent in non-occupational work with computer, minutes, median (IQR)	60.0 (40.0–120.0)
Number of additional breaks while occupationally working with computer (excluding the legal one of 30 minutes), median (IQR)	2.0 (2.0–4.0)
Total duration of additional breaks while occupationally working with computer, minutes, median (IQR)	6.0 (6.0–12.0)
Exercises (finger and thumb stretching and wrist and hand joints rotations) during breaks at work, n (%)	80 (42.1)
Exercises (finger and thumb stretching and wrist and hand joints rotations) during breaks outside of work, n (%)	71 (37.4)
Use of a mouse while occupationally working with computer, n (%)	190 (100.0)
Use of a mouse pad while occupationally working with computer, n (%)	162 (85.3)
Use of an ergonomically designed mouse, mouse pad, and keyboard (adapted to the anatomical characteristics of the user's hand) while occupationally working with computer, n (%)	74 (38.9)
Completed training for safe and healthy work with computers, n (%)	77 (40.5)
Other repetitive jobs with hands at the workplace not related to computer-work, n (%)	99 (52.1)
Other repetitive jobs with hands outside the workplace, n (%)	44 (23.2)
Heavy physical exertion with arms/hands at the workplace outside the computer-work, n (%)	28 (14.7)
Heavy physical exertion with arms/hands outside the workplace, n (%)	33 (17.4)
Exposure to vibrations at the workplace, n (%)	96 (50.5)
Duration of exposure to vibrations at the workplace, minutes, median (IQR)	10.0 (0.0–30.0)
The level of vibration at the workplace above >5 m/s² A(8), n (%)	5 (2.6)
Exposure to vibrations outside the workplace, n (%)	57 (30.0)
Air temperature at the workplace, n (%)
Normal	156 (82.1)
High	3 (1.6)
Low	31 (16.3)
Air temperature at the workplace, °C, median (IQR)	23.0 (18.0–26.0)
Relative air humidity at the workplace, n (%)
Normal	91 (47.9)
Low	3 (1.6)
High	96 (50.5)
Air-flow speed at the workplace, n (%)
Normal	92 (48.4)
Low	3 (1.6)
High	95 (50.0)
General job satisfaction, n (%)
Poorly satisfied	111 (58.4)
Moderately satisfied	66 (34.7)
Very satisfied	13 (6.8)

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with laboratory markers of inflammation and metabolic risk in the cohort of workers who work with a computer (N=190)

Variable	Boston Carpal Tunnel Questionnaire (BCTQ)		Electrodiagnostic (EDX) testing							Work disability related to CTS
	SSS score	FSS score	Median nerve MCV	Median nerve SCV	Median nerve SDOL	Ulnar nerve MCV	Ulnar nerve SCV	Ulnar nerve SDOL	Median / ulnar nerve SDOL-R	Temporary work disability duration	Permanent work disability application	Recommended job change
	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_rb ^#	r_rb^#
Laboratory biochemical indicators of metabolic risk and inflammation
LDL-cholesterol	0.829^**	0.851^**	−0.980^**	−0.980^**	0.972^**	−0.190^**	−0.173^*	0.424^**	0.891^**	0.976^**	0.689^**	0.672^**
HDL-cholesterol	−0.847^**	−0.856^**	0.944^**	0.942^**	−0.932^**	0.175^*	0.162^*	−0.415^**	−0.848^**	−0.938^**	−0.668^**	−0.653^**
Triglycerides	0.850^**	0.864^**	−0.839^**	−0.835^**	0.830^**	−0.182^*	−0.173^*	0.403^**	0.738^**	0.836^**	0.670^**	0.687^**
Glucose	0.767^**	0.772^**	−0.678^**	−0.674^**	0.686^**	−0.124	−0.114	0.318^**	0.613^**	0.705^**	0.561^**	0.600^**
AST	0.041	−0.015	0.059	0.061	−0.047	−0.021	−0.024	0.062	−0.015	−0.055	−0.160^*	−0.115
ALT	0.414^**	0.395^**	−0.358^**	−0.354^**	0.366^**	−0.079	−0.066	0.175^*	0.284^**	0.349^**	0.381^**	0.333^**
GGT	0.275^**	0.308^**	−0.195^**	−0.188^**	0.188^**	0.008	0.027	0.017	0.183^*	0.201^**	0.258^**	0.244^**
Uric acid	0.593^**	0.583^**	−0.472^**	−0.470^**	0.470^**	−0.152^*	−0.144^*	0.268^**	0.512^**	0.465^**	0.445^**	0.543^**
Urea	0.702^**	0.705^**	−0.668^**	−0.666^**	0.653^**	−0.064	−0.047	0.443^**	0.635^**	0.660^**	0.531^**	0.685^**
Creatinine	0.601^**	0.622^**	−0.639^**	−0.640^**	0.624^**	−0.237^**	−0.221^**	0.353^**	0.576^**	0.640^**	0.446^**	0.604^**
ESR	0.846^**	0.862^**	−0.833^**	−0.832^**	0.824^**	−0.151^*	−0.140	0.376^**	0.803^**	0.837^**	0.710^**	0.757^**
Fibrinogen	0.683^**	0.712^**	−0.611^**	−0.613^**	0.612^**	−0.176^*	−0.164^*	0.291^**	0.603^**	0.617^**	0.585^**	0.627^**
CRP	0.852^**	0.869^**	−0.973^**	−0.973^**	0.975^**	−0.199^**	−0.183^*	0.405^**	0.891^**	0.977^**	0.701^**	0.666^**

Inter-correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS, and their correlation with other clinical characteristics of CTS and personal (demographic, anthropometric, overall health status and lifestyle) factors in the cohort of workers who work with a computer (N=190)

Variable	Boston Carpal Tunnel Questionnaire (BCTQ)		Electrodiagnostic (EDX) testing							Work disability related to CTS
	SSS score	FSS score	Median nerve MCV	Median nerve SCV	Median nerve SDOL	Ulnar nerve MCV	Ulnar nerve SCV	Ulnar nerve SDOL	Median to ulnar nerve SDOL-R	Temporary work disability duration	Permanent work disability application	Recommended job change
	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_rb / φ ^#	r_rb / φ ^#
Boston Carpal Tunnel Questionnaire (BCTQ)
Symptom Severity Scale (SSS) score	-	0.944^**	−0.840^**	−0.840^**	0.842^**	−0.230^**	−0.218^**	0.416^**	0.777^**	0.841^**	0.697^**	0.708^**
Functional Status Scale (FSS) score	0.944^**	-	−0.856^**	−0.853^**	0.851^**	−0.205^**	−0.194^**	0.422^**	0.792^**	0.856^**	0.688^**	0.722^**
Electrodiagnostic (EDX) testing
Median motor conduction velocity (MCV) m/s	−0.840^**	−0.856^**	-	0.998^**	−0.984^**	0.207^**	0.187^**	−0.428^**	−0.899^**	−0.986^**	−0.695^**	−0.676^**
Median sensory conduction velocity (SCV) m/s	−0.840^**	−0.853^**	0.998^**	-	−0.984^**	0.204^**	0.183^**	−0.428^**	−0.901^**	−0.985^**	−0.694^**	−0.677^**
Median sensory distal onset latency (SDOL) on ring finger, ms	0.842^**	0.851^**	−0.984^**	−0.984^**	-	−0.210^**	−0.194^**	0.422^**	0.907^**	0.985^**	0.699^**	0.669^**
Ulnar motor conduction velocity (MCV), m/s	−0.230^**	−0.205^**	0.207^**	0.204^**	−0.210^**	-	0.984^**	−0.161^*	−0.234^**	−0.200^**	−0,072	−0.170^**
Ulnar sensory conduction velocity (SCV) m/s	−0.218^**	−0.194^**	0.187^**	0.183^**	−0.194^**	0.984^**	-	−0.164^*	−0.224^**	−0.184^**	−0,063	−0.156^*
Ulnar sensory distal onset latency (SDOL) on ring finger, ms	0.416^**	0.422^**	−0.428^**	−0.428^**	0.422^**	−0.161^*	−0.164^*	-	0.378^**	0.397^**	0.270^**	0.459^**
Median to ulnar ratio of sensory distal onset latency (SDOL-R) on ring finger	0.777^**	0.792^**	−0.899^**	−0.901^**	0.907^**	−0.234^**	−0.224^**	0.378^**	-	0.894^**	0.634^**	0.703^**
Work disability indicators
Duration of temporary work disability related to CTS, days	0.841^**	0.856^**	−0.986^**	−0.985^**	0.985^**	−0.200^**	−0.184^**	0.397^**	0.894^**	-	0.702^**	0.673^**
Applications for permanent work disability because of CTS	0.697^**	0.688^**	−0.695^**	−0.694^**	0.699^**	−0.072	−0.063	0.270^**	0.634^**	0.702^**	-	0.678^**
Recommended job change because of CTS	0.708^**	0.722^**	−0.676^**	−0.677^**	0.669^**	−0.170^**	−0.156^*	0.459^**	0.703^**	0.673^**	0.678^**	-
Other clinical characteristics
Duration of CTS since diagnosis, months	0.843^**	0.857^**	−0.985^**	−0.984^**	0.979^**	−0.206^**	−0.188^**	0.424^**	0.888^**	0.989^**	0.684^**	0.680^**
Bilateral presentation	0.419^**	0.420^**	−0.334^**	−0.330^**	0.334^**	−0.211^**	−0.197^**	0.187^**	0.300^**	0.332^**	0.307^**	0.343^**
Family history for CTS	0.438^**	0.446^**	−0.379^**	−0.372^**	0.395^**	−0.284^**	−0.275^**	0.293^**	0.409^**	0.387^**	0.397^**	0.498^**
Treatment options (medication, physical therapy included, or also surgery included)	0.512^**	0.500^**	−0.416^**	−0.417^**	0.426^**	−0.168^*	−0.162^*	0.300^**	0.427^**	0.424^**	0.296^**	0.399^**
Steroidal anti-inflammatory medication included	0.673^**	0.668^**	−0.585^**	−0.581^**	0.582^**	−0.264^**	−0.253^**	0.399^**	0.570^**	0.586^**	0.550^**	0.742^**
Non-steroidal anti-inflammatory medication included	0.587^**	0.578^**	−0.590^**	−0.584^**	0.581^**	−0.244^**	−0.231^**	0.320^**	0.500^**	0.584^**	0.478^**	0.582^**
Medication only	−0.290^**	−0.286^**	0.156^*	0.159^*	−0.176^*	0.015	0.024	−0.041	−0.203^**	−0.175^*	−0.225^**	−0.261^**
Physical therapy included	−0.076	−0.065	0.062	0.063	−0.056	0.093	0.082	−0.171^*	−0.081	−0.049	0.054	0.003
Surgery included	0.257^**	0.243^**	−0.161^*	−0.164^*	0.167^*	−0.107	−0.101	0.203^**	0.209^**	0.159^*	0.082	0.157^*
Personal demographic, anthropometric, overall health status and lifestyle factors
Female gender	0.633^**	0.637^**	−0.494^**	−0.493^**	0.480^**	−0.246^**	−0.239^**	0.343^**	0.541^**	0.482^**	0.480^**	0.723^**
Age, years	0.836^**	0.850^**	−0.985^**	−0.984^**	0.987^**	−0.212^**	−0.194^**	0.412^**	0.909^**	0.990^**	0.681^**	0.670^**
Educational status	−0.295^**	−0.270^**	0.259^**	0.266^**	−0.265^**	−0.003	−0.012	−0.018	−0.276^**	−0.243^**	−0.299^**	−0.294^**
Undergraduate (high school)	0.299^**	0.277^**	−0.272^**	−0.279^**	0.276^**	0.001	0.007	0.022	0.290^**	0.254^**	0.303^**	0.285^**
Graduate (university)	−0.286^**	−0.270^**	0.281^**	0.287^**	−0.280^**	0.005	0.003	−0.028	−0.301^**	−0.259^**	−0.291^**	−0.244^**
Postgraduate	−0.048	−0.026	−0.023	−0.017	0.008	−0.019	−0.032	0.018	0.027	0.012	−0.044	−0.133^*
Body mass index, kg/m²	0.803^**	0.805^**	−0.835^**	−0.834^**	0.831^**	−0.145^*	−0.138^*	0.303^**	0.765^**	0.838^**	0.640^**	0.611^**
Systolic blood pressure, mm Hg	0.736^**	0.767^**	−0.687^**	−0.685^**	0.697^**	−0.271^**	−0.256^**	0.380^**	0.659^**	0.700^**	0.585^**	0.715^**
Diastolic blood pressure, mm Hg	0.736^**	0.757^**	−0.690^**	−0.689^**	0.697^**	−0.269^**	−0.259^**	0.365^**	0.679^**	0.706^**	0.596^**	0.719^**
Other diseases	0.593^**	0.613^**	−0.435^**	−0.429^**	0.447^**	−0.149^*	−0.139^*	0.166^*	0.446^**	0.455^**	0.425^**	0.522^**
Diseases of endocrine glands (diabetes, thyroid disease)	0.515^**	0.524^**	−0.365^**	−0.359^**	0.365^**	−0.255^**	−0.262^**	0.172^**	0.348^**	0.375^**	0.419^**	0.433^**
Smoking habit	0.630^**	0.631^**	−0.459^**	−0.456^**	0.458^**	−0.077	−0.075	0.250^**	0.420^**	0.472^**	0.492^**	0.597^**
Alcohol consumption	0.686^**	0.730^**	−0.621^**	−0.612^**	0.626^**	−0.149^*	−0.151^*	0.320^**	0.591^**	0.636^**	0.547^**	0.665^**
Physical activity level	−0.605^**	−0.621^**	0.753^**	0.752^**	−0.750^**	0.306^**	0.320^**	−0.392^**	−0.707^**	−0.753^**	−0.424^**	−0.492^**
Physical activity METs scores, min week⁻¹	−0.772^**	−0.772^**	0.738^**	0.734^**	−0.738^**	0.306^**	0.312^**	−0.430^**	−0.689^**	−0.746^**	−0.585^**	−0.705^**

Dietary habits and consumption of food supplements among study participants

Food groups / Dietary supplements	Frequency
	Never or less than once a month	Once a month to once a week	Two of more times a week
	All (N=190)
Food groups
Consumes refined grain products (e.g., white bread, pasta, puff pastry) in his/her diet, n (%)	23 (12.1)	43 (22.6)	124 (65.3)
Consumes integral grain products (e.g., integral bread, flakes, muesli) in his/her diet, n (%)	137 (72.1)	19 (10.0)	34 (17.9)
Consumes dairy products in his diet, n (%)	23 (12.1)	98 (51.6)	69 (36.3)
Consumes eggs in his/her diet, n (%)	123 (64.7)	31 (16.30)	36 (18.9)
Consumes poultry meat in his/her diet, n (%)	123 (64.7)	35 (18.4)	32 (16.8)
Consumes red and processed meat in his/her diet, n (%)	27 (14.2)	72 (37.9)	91 (47.9)
Consumes fish and seafood in his/her diet, n (%)	132 (69.5)	31 (16.3)	27 (14.2)
Consumes fresh vegetables (in salad) in his/her diet, n (%)	140 (73.7)	17 (8.9)	33 (17.4)
Consumes legumes (e.g., beans, peas, lentils, green beans) in his/her diet, n (%)	41 (21.6)	75 (39.5)	74 (38.9)
Consumes fresh fruit in his/her diet, n (%)	136 (71.6)	20 (10.5)	34 (17.9)
Consumes nuts (e.g., almonds, walnuts, hazelnuts) in his/her diet, n (%)	129 (67.9)	30 (15.8)	31 (16.3)
Consumes sunflower oil in his/her diet, n (%)	127 (66.8)	37 (19.5)	26 (13.7)
Consumes olive oil in his/her diet, n (%)	144 (75.8)	13 (6.8)	33 (17.4)
Consumes pork lard in his/her diet, n (%)	148 (77.9)	24 (12.6)	18 (9.5)
Consumes tallow in his/her diet, n (%)	4 (2.1)	19 (10.0)	167 (87.9)
Consumes sweets in his/her diet, n (%)	27 (14.2)	25 (13.2)	138 (72.6)
Consumes dry fruits in his/her diet, n (%)	25 (13.2)	53 (27.9)	112 (58.9)
Consumes spirits in his/her diet, n (%)	32 (16.8)	36 (18.9)	122 (64.2)
Consumes beer in his/her diet, n (%)	136 (71.6)	19 (10.0)	35 (18.4)
Consumes wine in his/her diet, n (%)	53 (27.9)	86 (45.3)	51 (26.8)
Consumes carbonated drinks with sugar and energy drinks in his/her diet, n (%)	40 (21.1)	29 (15.3)	121 (63.7)
Consumes freshly squeezed juices in his/her diet, n (%)	138 (72.6)	18 (9.5)	34 (17.9)
Dietary supplements
Consumes vitamin A supplements, n (%)	91 (47.9)	62 (32.6)	37 (19.5)
Consumes vitamin D supplements, n (%)	109 (57.4)	50 (26.3)	31 (16.3)
Consumes vitamin E supplements, n (%)	113 (59.5)	47 (24.7)	30 (15.8)
Consumes vitamin C supplements, n (%)	106 (55.8)	55 (28.9)	29 (15.3)
Consumes vitamin B group supplements, n (%)	112 (58.9)	44 (23.2)	34 (17.9)
Consumes folic acid supplements, n (%)	120 (63.2)	46 (24.2)	24 (12.6)
Consumes calcium supplements, n (%)	113 (59.5)	48 (25.3)	29 (15.3)
Consumes magnesium supplements, n (%)	114 (60.0)	52 (27.4)	24 (12.6)
Consumes iron supplements, n (%)	118 (62.1)	63 (33.2)	9 (4.7)
Consumes zinc supplements, n (%)	119 (62.6)	45 (23.7)	26 (13.7)
Consumes selenium supplements, n (%)	123 (64.7)	41 (21.6)	26 (13.7)
Consumes fish oil omega-3 supplements, n (%)	113 (59.5)	42 (22.1)	35 (18.4)
Consumes probiotic preparations, n (%)	113 (59.5)	39 (20.5)	38 (20.0)

Demographic, anthropometric, health, and lifestyle characteristics of the study participants (N=190)

Variable	All subjects (N=190)
Male gender, n (%)	90 (47.4)
Female gender, n (%)	100 (52.6)
Age, years, median (IQR)	36.0 (28.8–51.0)
<35 years old, n (%)	79 (41.6)
35–50 years old, n (%)	63 (33.2)
>50 years old, n (%)	48 (25.3)
Undergraduate education (high school) (n %)	106 (55.8)
Graduate education (university) (n %)	79 (41.6)
Postgraduate education (n %)	5 (2.6)
Right hand dominant, n (%)	176 (92.6)
Left hand dominant, n (%)	14 (7.4)
Body mass index, kg/m², median (IQR)	26.0 (23.8–27.8)
Normal-weight, n (%)	75 (39.5)
Overweight, n (%)	96 (50.5)
Obese, n (%)	19 (10.0)
Systolic blood pressure, mm Hg, median (IQR)	145.0 (125.0–155.0)
Diastolic blood pressure, mm Hg, median (IQR)	95.0 (80.0–105.0)
Hypertension, n (%)	111 (58.4)
Other cardiovascular diseases (apart from hypertension), n (%)	5 (2.6)
Diseases of endocrine glands (diabetes, thyroid disease), n (%)	96 (50.5)
Diseases of the blood and blood-forming organs, n (%)	8 (4.2)
Mental disorders, n (%)	1 (0.5)
Diseases of the genitourinary system, n (%)	4 (2.1)
Other diseases of the musculoskeletal system unrelated to CTS, n (%)	20 (10.5)
Never smoker / former smoker, n (%)	49 (25.8)
Current smoker, n (%)	141 (74.2)
<10 cigarettes a day, n (%)	20 (10.5)
10–20 cigarettes a day, n (%)	52 (27.4)
>20 cigarettes a day, n (%)	69 (36.3)
No alcohol consumption, n (%)	63 (33.2)
Moderate alcohol consumption, n (%)	68 (35.8)
Occasional alcohol overconsumption, n (%)	51 (26.8)
Frequent alcohol overconsumption, n (%)	8 (4.2)
Low physical activity, n (%)	138 (72.6)
Intermediate physical activity, n (%)	41 (21.6)
High physical activity, n (%)	11 (5.8)
Physical activity METs scores, min week⁻¹, median (IQR)	0.0 (0.0–1512.0)

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with occupational factors related or not related to work with computer in the cohort of workers who work with a computer (N=190)

Variable	Boston Carpal Tunnel Questionnaire (BCTQ)		Electrodiagnostic (EDX) testing							Work disability related to CTS
	SSS score	FSS score	Median nerve MCV	Median nerve SCV	Median nerve SDOL	Ulnar nerve MCV	Ulnar nerve SCV	Ulnar nerve SDOL	Median / ulnar nerve SDOL-R	Temporary work disability duration	Permanent work disability application	Recommended job change
	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_s / r_rb ^§	r_rb / φ^#	r_rb / φ ^#
Occupational factors – computer work related
Duration of occupational work with computer, months	0.842^**	0.855^**	−0.990^**	−0.988^**	0.985^**	−0.201^**	−0.183^**	0.425^**	0.898^**	0.990^**	0.689^**	0.675^**
Average daily time spent in occupational work with computer, minutes	0.844^**	0.856^**	−0.984^**	−0.983^**	0.984^**	−0.193^**	−0.175^**	0.415^**	0.880^**	0.988^**	0.698^**	0.676^**
Total time in occupational computer work (minutes × months)	0.841^**	0.853^**	−0.988^**	−0.986^**	0.985^**	−0.196^**	−0.178^*	0.421^**	0.982^**	0.989^**	0.689^**	0.673^**
Average daily time spent in non-occupational work with computer, minutes	0.855^**	0.869^**	−0.987^**	−0.985^**	0.983^**	−0.203^**	−0.184^*	0.424^**	0.893^**	0.987^**	0.703^**	0.687^**
Number of additional breaks while occupationally working with computer	−0.721^**	−0.751^**	0.823^**	0.821^**	−0.826^**	0.233^**	0.217^**	−0.409^**	−0.779^**	−0.826^**	−0.591^**	−0.683^**
Total duration of additional breaks while occupationally working with computer, minutes	−0.728^**	−0.760^**	0.829^**	0.827^**	−0.832^**	0.238^**	0.223^**	−0.417^**	−0.782^**	−0.833^**	−0.589^**	−0.681^**
Exercises (finger and thumb stretching and wrist and hand joints rotations) during breaks at work	−0.718^**	−0.736^**	0.614^**	0.611^**	−0.617^**	0.228^**	0.222^**	−0.312^**	−0.594^**	−0.625^**	−0.571^**	−0.667^**
Exercises (finger and thumb stretching and wrist and hand joints rotations) during breaks outside of work	−0.769^**	−0.781^**	0.663^**	0.660^**	−0.662^**	0.238^**	0.232^**	−0.359^**	−0.648^**	−0.668^**	−0.514^**	−0.602^**
Use of a mouse pad while occupationally working with computer	0.016	0.014	−0.223^**	−0.225^**	0.229^**	0.172^**	0.184^**	0.052	0.186^**	0.217^**	0.099	0.032
Use of an ergonomically designed mouse, mouse pad, and keyboard (adapted to the anatomical characteristics of the user's hand) while occupationally working with computer	−0.773^**	−0.811^**	0.649^**	0.649^**	−0.649^**	0.258^**	0.252^**	−0.369^**	−0.644^**	−0.660^**	−0.531^**	−0.621^**
Completed training for safe and healthy work with computers	−0.742^**	−0.770^**	0.598^**	0.598^**	−0.596^**	0.249^**	0.243^**	−0.347^**	−0.574^**	−0.609^**	−0.529^**	−0.645^**
Occupational factors – not computer work related
Other repetitive jobs with hands at the workplace not related to computer-work	0.772^**	0.757^**	−0.691^**	−0.685^**	0.685^**	−0.234^**	−0.221^**	0.418^**	0.646^**	0.685^**	0.600^**	0.688^**
Other repetitive jobs with hands outside the workplace	0.197^**	0.211^**	−0.137^*	−0.130^*	0.120^*	−0.094	−0.092	0.313^**	0.151^*	0.147^*	0.257^**	0.373^**
Heavy physical exertion with arms/hands at the workplace outside the computer-work	0.043	0.063	0.038	0.043	−0.025	−0.184^**	−0.185^**	0.091	−0.008	−0.024	−0.004	−0.002
Heavy physical exertion with arms/hands outside the workplace	0.040	0.042	0.083	0.089	−0.088	−0.266^**	−0.271^**	0.081	−0.060	−0.076	−0.052	0.028
Exposure to vibrations at the workplace	0.772^**	0.780^**	−0.741^**	−0.736^**	0.746^**	−0.198^**	−0.186^*	0.442^**	0.697^**	0.750^**	0.576^**	0.670^**
Duration of exposure to vibrations at the workplace, minutes	0.795^**	0.802^**	−0.772^**	−0.768^**	0.779^**	−0.119	−0.105	0.443^**	0.719^**	0.781^**	0.714^**	0.766^**
The level of vibration at the workplace above limit	0.042	0.089	−0.047	−0.043	0.042	−0.005	−0.010	−0.018	0.070	0.057	0.096	0.204^**
Exposure to vibrations out of work	0.795^**	0.802^**	−0.772^**	−0.768^**	0.779^**	−0.119	−0.105	0.443^**	0.719^**	0.781^**	0.714^**	0.766^**
Air temperature at the workplace
Normal	−0.605^**	−0.613^**	0.665^**	0.664^**	−0.664^**	0.043	0.035	−0.105	−0.557^**	−0.665^**	−0.612^**	−0.353^**
Increased	0.056	0.073	−0.146^*	−0.144^*	0.147^*	−0.078	−0.077	0.021	0.153^*	0.145^*	0.002	−0.102
Decreased	0.609^**	0.612^**	−0.640^**	−0.640^**	0.639^**	−0.018	−0.010	0.102	0.526^**	0.641^**	0.634^**	0.401^**
Air temperature at the workplace, degrees Celsius	−0.850^**	−0.856^**	0.985^**	0.983^**	−0.982^**	0.176^**	0.158^*	−0.418^**	−0.891^**	−0.988^**	−0.701^**	−0.681^**
Relative air humidity at the workplace
Normal	−0.772^**	−0.767^**	0.715^**	0.710^**	−0.714^**	0.254^**	0.241^**	−0.418^**	−0.667^**	−0.720^**	−0.555^**	−0.666^**
Decreased	0.056	0.073	−0.146^*	−0.144^*	0.147^*	−0.078	−0.077	0.021	0.153^*	0.145^*	0.002	−0.102
Increased	0.758^**	0.748^**	−0.678^**	−0.674^**	0.677^**	−0.234^**	−0.222^**	0.413^**	0.628^**	0.683^**	0.554^**	0.691^**
Air-flow speed at the workplace
Normal	−0.778^**	−0.769^**	0.735^**	0.730^**	−0.735^**	0.222^**	0.210^**	−0.416^**	−0.687^**	−0.732^**	−0.584^**	−0.653^**
Decreased	0.056	0.073	−0.146^*	−0.144^*	0.147^*	−0.078	−0.077	0.021	0.153^*	0.145^*	0.002	−0.102
Increased	0.763^**	0.751^**	−0.698^**	−0.694^**	0.698^**	−0.203^**	−0.191^**	0.410^**	0.648^**	0.696^**	0.584^**	0.678^**
General job satisfaction	−0.738^**	−0.750^**	0.593^**	0.590^**	−0.596^**	0.225^**	0.229^**	−0.327^**	−0.573^**	−0.602^**	−0.534^**	−0.648^**
Poorly satisfied	0.740^**	0.749^**	−0.581^**	−0.578^**	0.584^**	−0.220^**	−0.215^**	0.324^**	0.564^**	0.589^**	0.542^**	0.659^**
Moderately satisfied	−0.610^**	−0.608^**	0.443^**	0.441^**	−0.447^**	0.168^*	0.142^*	−0.257^**	−0.435^**	−0.446^**	−0.461^**	−0.567^**
Very satisfied	−0.296^**	−0.315^**	0.298^**	0.298^**	−0.297^**	0.114	0.152^*	−0.147^*	−0.280^**	−0.309^**	−0.189^**	−0.219^**

Biochemical laboratory markers of inflammation and metabolic risk among study participants

Variable	All (N=190)
LDL-cholesterol, mmol/L, median (IQR)	3.6 (2.7–4.4)
HDL-cholesterol, mmol/L, median (IQR)	0.9 (0.7–1.3)
Triglycerides, mmol/L, median (IQR)	1.7 (1.4–1.9)
Glucose, mmol/L, median (IQR)	5.6 (4.9–6.3)
AST, IU/L, median (IQR)	35.5 (20.0–41.0)
ALT, IU/L, median (IQR)	41.0 (35.0–51.3)
GGT, IU/L, median (IQR)	47.0 (38.0–58.0)
Uric acid, mmol/L, median (IQR)	416.0 (285.0–430.0)
Urea, mmol/L, median (IQR)	8.5 (6.5–9.3)
Creatinine, mmol/L, median (IQR)	92.0 (49.5–102.4)
ESR, mm/h, median (IQR)	20.0 (15.0–28.0)
Fibrinogen, g/L, median (IQR)	4.0 (3.2–4.7)
CRP, mg/L, median (IQR)	5.7 (4.0–7.9)

Medical history related to CTS, subjective and objective impairments (BCSQ and EDX results) and work disability indicators

Variable	All (N=190)
Duration of CTS since diagnosis, months, median (IQR)	40.0 (15.0–130.0)
Affected hand, n (%)
Dominant	88 (46.3)
Non-dominant	18 (9.5)
Bilateral	84 (44.2)
Family history of CTS, yes, n (%)	96 (50.5)
Treatment, n (%)
Medication only	18 (9.5)
Physical therapy included, without surgery	106 (55.8)
Surgery included	66 (34.7)
Steroidal anti-inflammatory medication included, n (%)	103 (54.2)
Non-steroidal anti-inflammatory medication included, n (%)	125 (65.8)
Boston Carpal Tunnel Questionnaire (BCTQ)
Symptom Severity Scale (SSS) score, range 1–5, median (IQR)	2.9 (1.0–4.1)
Functional Status Scale (FSS) score, range 1–5, median (IQR)	2.6 (1.0–4.1)
Electrodiagnostic (EDX) testing
Motor conduction velocity (MCV) of n. medianus, m/s, median (IQR)	49.5 (41.0–57.0)
Sensory conduction velocity (SCV) of n. medianus, m/s, median (IQR)	50.0 (41.0–58.0)
Sensory distal onset latency (SDOL) of n. medianus, ms, median (IQR)	1.2 (0.8–2.0)
Motor conduction velocity (MCV) of n. ulnaris, m/s, median (IQR)	58.0 (57.0–60.0)
Sensory conduction velocity (SCV) of n. ulnaris, m/s, median (IQR)	59.0 (58.0–61.0)
Sensory distal onset latency (SDOL) of n. unaris, ms, median (IQR)	1.6 (1.5–1.6)
Ratio of distal sensory latency (SDOL-R) of n. medianus and n. unaris, median (IQR)	0.8 (0.5–1.3)
Work disability indicators
Duration of temporary work disability related to CTS during the preceding year, days, median (IQR)	31.5 (14.0–50.0)
Applications for permanent work disability because of CTS, n (%)	62 (32.6)
Job changes because of CTS, n (%)	75 (39.5)

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with frequency of consumption of certain food groups and dietary supplements in the cohort of workers who work with a computer (N=190)

Variable	Boston Carpal Tunnel Questionnaire (BCTQ)		Electrodiagnostic (EDX) testing							Work disability related to CTS
	SSS score	FSS score	Median nerve MCV	Median nerve SCV	Median nerve SDOL	Ulnar nerve MCV	Ulnar nerve SCV	Ulnar nerve SDOL	Median / ulnar nerve SDOL-R	Temporary work disability duration	Permanent work disability application	Recommended job change
	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_s ^§	r_rb ^#	r_rb^#
Frequency of food groups and dietary supplements consumption
Frequency of consumption of refined grain products, red and processed meat, tallow, sweets, dried fruits, carbonated sugar-added beverages and spirits (dietary cluster 1)	0.621^**	0.620^**	0.531^**	0.539^**	−0.551^**	−0.289^**	−0.283^**	0.194^**	0.554^**	0.564^**	0.453^**	0.412^**
Frequency of consumption of integral grain products, eggs, poultry, fish and sea products, fresh vegetables, fresh fruits and fruit-juices, nuts, vegetable oils (including sunflower oil and olive oil), pork lard, and beer (dietary cluster 2)	−0.748^**	−0.721^**	0.723^**	0.722^**	−0.723^**	0.298^**	0.287^**	−0.343^**	−0.725^**	−0.731^**	−0.550^**	−0.607^**
Frequency of use of all dietary supplements (all examined supplements included)	−0.800^**	−0.806^**	0.847^**	0.844^**	−0.848^**	0.285^**	0.274^**	−0.410^**	−0.843^**	−0.852^**	−0.595^**	−0.677^**

Occupational and non-occupational risk factors correlating with the severity of clinical manifestations of carpal tunnel syndrome and related work disability among workers who work with a computer

Figures & Tables

Participants’ data on occupational factors related and not related to computer-work

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with laboratory markers of inflammation and metabolic risk in the cohort of workers who work with a computer (N=190)

Dietary habits and consumption of food supplements among study participants

Demographic, anthropometric, health, and lifestyle characteristics of the study participants (N=190)

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with occupational factors related or not related to work with computer in the cohort of workers who work with a computer (N=190)

Biochemical laboratory markers of inflammation and metabolic risk among study participants

Medical history related to CTS, subjective and objective impairments (BCSQ and EDX results) and work disability indicators

Correlations of indicators of subjective and objective impairments (BCSQ and EDX results) and work disability related to CTS with frequency of consumption of certain food groups and dietary supplements in the cohort of workers who work with a computer (N=190)

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