Occuptionl Medicine Advnce Access published Jnury 13, 2014 Occuptionl Medicine doi:10.1093/occmed/kqt160 Slips, trips nd flls t chemicl mnufcturing compny G. Swen, C. J. Burns, J. J. Collins, K. M. Bodner, J. F. Dizor, B. A. Crun nd E. M. Bonner The Dow Chemicl Compny, Midlnd, MI 48674, USA. Correspondence to: J. J. Collins, Epidemiology, The Dow Chemicl Compny, 1803 Building, Midlnd, MI 48674, USA. Tel: +1 989 636 1276; fx: +1 989 636 1875; e-mil: jjcollins@dow.com Bckground Slips, trips nd flls (STF) re mjor cuse of workplce injury. Aims Methods Results To exmine risk fctors for STF t lrge US chemicl mnufcturing compny. We conducted cse control study of occuptionl STF. Cses were identified from compny injury records between 1 April 2009 nd 1 My 2011. Four controls per cse were rndomly selected from ll ctive compny workers employed during the sme time. Dt were collected through questionnire nd from compny medicl exmintions. Logistic regression ws used to clculte odds rtio (OR) nd 95% confidence intervls (95% CI) for personl, environmentl nd helth-relted risk fctors for STF. There were 74 cses nd 309 controls. The response rte ws 65% for the cses nd 68% for the controls. Most STF were unrelted to production ctivities. When exmining ll fctors in logistic regression model, incresed OR were observed for incresed body mss index (OR = 1.44, 95% CI: 1.03 2.02), hving rthritis (OR = 2.11, 95% CI: 1.01 4.37), lck of exercise (OR = 2.25, 95% CI: 1.01 5.05), crrying mterils (OR = 3.01, 95% CI: 1.41 6.43) nd being femle (OR = 2.46, 95% CI: 1.17 5.19). Reduced risk of STF ws observed for never hving smoked (OR = 0.48, 95% CI: 0.24 0.95), long service (OR = 0.53, 95% CI: 0.34 0.81) nd persons working over 8 h dy (OR = 0.42, 95% CI: 0.20 0.88). Conclusions Risk fctors for STF in lrge US chemicl compny re similr to those reported from other workplces, but we found tht stying fit nd helthy is importnt for reducing risk. Key words Arthritis; body mss index; flls; injury; slips; smoking; trips. Introduction Slips, trips nd flls (STF) re leding cuse of workplce injuries [1]. In the USA, the nnul cost of these to industry is estimted t $5.7 billion [2]. Severl studies hve exmined cuses of STF in workplces including mnufcturing [3 6] nd industry in generl [7 10]. These studies hve shown tht flls result from both personl nd environmentl fctors. Personl risk fctors include sex [6,9 13], ge [7,9 12,14,15], ftigue [16 20], obesity [8,16,17,21,22], smoking [17], lcohol consumption [17], physicl inctivity [15,17,23], low fitness levels [15,23], low eduction level [8], somtic complints [8] nd job strin [24]. Studies of older persons ssocite incresed risk with vision impirment, hering problems, functionl limittions, pst flls, low physicl ctivity, physicl performnce, nd unstedy wlk nd imblnce [14]. Environmentl fctors such s footwer [7,25,26] nd surfce conditions [3,7,27,28] lso increse the risk of workplce STFs. Understnding the cuses of STFs enbles intervention to reduce their incidence. Most occuptionl injuries re reviewed on cse only bsis s prt of root cuse investigtion. Root cuse investigtions re conducted to understnd better wht fctors hve contributed to n injury nd wht mesures must be tken to prevent these in the future. Extensive efforts re undertken within compnies to eliminte STF, but few epidemiologicl studies hve identified personl- or work-relted fctors ssocited with risk from these injuries. While root cuse investigtions re imed t individul events, n epidemiologicl pproch nlyzes the entire popultion. Expnding nlyses to higher, more ggregte level by compring group with personl injury from STF with n pproprite The Author 2014. Published by Oxford University Press on behlf of the Society of Occuptionl Medicine. All rights reserved. For Permissions, plese emil: journls.permissions@oup.com
Pge 2 of 6 OCCUPATIONAL MEDICINE comprison group cn yield importnt insights into further eliminting these types of injuries not found in root cuse investigtion. Few studies hve employed comprison groups to formlly identify risk fctors. In this study, we exmine STF in lrge US chemicl compny using cse control design to better determine the personl nd environmentl cuses. Methods We included ll US fcilities of lrge multintionl chemicl compny, whose products re used in building nd construction, helth nd medicine, trnsporttion, pints nd coting, electronics, phrmceuticls nd food. Much of the chemicl production is utomted. Severl mnufcturing fcilities lso hve reserch nd development lbortories. Ethicl pprovl for the study ws obtined from the Humn Subjects Review Bord in Midlnd, Michign. The purpose of the study ws explined to prticipnts nd confidentility ssured. All respondents provided informed consent. We collected dt in August 2011. We included workers employed on 1 My 2011, who hd worked since t lest 1 April 2009, to ensure cses nd controls ll worked in the sme time period. Cses included ll employees with recorded STF tht occurred between April 2009 nd My 2011. To llow for dely in recording STF cses, dt were collected from prticipnts employed in August 2011. The study ws restricted to US employees to void problems with registrtion, lnguge nd confidentility in other countries. We identified controls from compny personnel files. We rndomly selected four controls working between 1 April 2009 nd 1 My 2011 for ech cse, representing rnge of loctions nd birth yers. We chose not to mtch on these fctors so tht they could be nlysed s potentil determinnts. We contcted ll cndidte cse nd control subjects by compny e-mil nd invited them to prticipte. We dministered questionnire to respondents. We sked bout generl work fctors, working with mchines tht might cuse injury, ttitudes to occuptionl sfety, job stress, ftigue nd personl fctors such s blnce, physicl ctivity nd helth conditions. We lso collected dt from compny medicl exmintions, including findings from physicl exmintions, height nd weight, current nd pst illnesses nd risk fctors for disese. The questionnire is vilble in the electronic version of the pper. We clculted undjusted odds rtios (OR) to identify potentil risk fctors. Since mny personl nd work cofctors my be relted to sex, we used logistic regression to djust for sex for ech fctor with P < 0.10. We used this P vlue to ssure tht potentil importnt predictive fctors were not excluded during the modelling process. We then grouped the vribles s work relted nd helth relted. We clculted OR nd 95% confidence intervls (95% CI). We rn seprte logistic regression models using bckwrds stepwise regression to identify the most prsimonious model with sex, yers of service nd body mss index (BMI) included in ech. We rn full model with ll significnt cofctors included from ech model. All nlyses were done with SAS [29]. Tble 1. Chrcteristics of STF cses nd controls nd differences compred with reference level using OR nd 95% confidence limits Chrcteristics Cses (%) Controls (%) OR 95% CI Prticipnts 74 (66) 309 (68) Totl recruited 113 (100) 452 (100) Sex Mle (reference level) 41 (55) 228 (74) 1.00 Femle 33 (45) 81 (26) 2.27 1.34 3.83 Birth decde 1940 6 (8) 9 (3) 3.50 1.12 10.93 1950 (reference level) 20 (27) 105 (34) 1.00 1960 27 (37) 120 (39) 1.18 0.62 2.23 1970 14 (19) 54 (18) 1.36 0.64 2.90 1980 7 (10) 21 (7) 1.17 0.66 4.66 Yers of service <5 (reference level) 22 (30) 33 (11) 1.00 5 14 21 (28) 86 (28) 0.37 0.18 0.75 15 24 18 (24) 104 (34) 0.26 0.12 0.54 25 13 (18) 86 (28) 0.23 0.10 0.50 BMI (kg/m 2 ) <25 norml weight (reference level) 14 (23) 78 (27) 1.00 25 29 overweight 16 (26) 116 (40) 0.52 0.26 1.03 30 34 obese 19 (31) 67 (23) 1.07 0.55 2.09 35 very obese 13 (21) 28 (10) 1.75 0.80 3.85 Percentges were clculted fter excluding subject with missing vlue for the vrible in question.
G. SWAEN ET AL.: SLIPS, TRIPS AND FALLS Pge 3 of 6 Results We identified 116 cses nd 464 controls. We were un ble to contct three cses nd we therefore invited 113 cses nd 452 controls to prticipte in the study. The response rtes were 65% (74/113) for cses nd 68% (309/383) for controls, for the 2-week recruitment period. The verge ge ws 47.4 in cses nd 47.0 in controls. This difference ws not sttisticlly significnt. Of the 74 cses of STF, 23% (17) occurred in office buildings, 43% (32) occurred outside, e.g. on prking lots, pvements nd sidewlks, of which 19 occurred on icy underground pthwys, 23% (17) occurred in production or distribution res, 9% (7) in reserch fcilities nd 1% in mintennce re. All injuries from STF were seen by medicl professionl. Injuries were minor in 63 of the 74 employees (85%) nd were coded s requiring only first id or precutionry visit to the compny medicl fcility. Only 11 prticipnts required work restrictions due to their STF. Tble 1 compres the sex, ge, length of service nd BMI distributions of cses nd controls. Women nd prticipnts born in the 1940s were t gretest risk of being cse. There ws n inverse ssocition between more yers of service nd cse sttus. Tbles 2 nd 3 compre work- nd helth-relted chrcteristics of cses nd controls without nd with djustment for sex. After djustment for sex, only the technicin job type ws Tble 2. Work-relted chrcteristics of the prticipnts in the study nd the OR nd 95% CI, crude nd djusted for sex Chrcteristics Crude OR Crude 95% CI OR djusted for sex 95% CI djusted for sex. Job type Administrtion 2.26 1.01 5.05* 1.50 0.63 3.57 Functionl specilist 0.48 0.28 0.83* 0.44 0.25 0.78 Leder Technicin 1.48 0.89 2.46 1.83 1.01 3.14* b. Stress relted I m lwys in hurry 0.51 0.28 0.92* 0.48 0.26 0.88* I mind if tsks tke longer 0.74 0.44 1.24 0.76 0.45 1.28 I get distrcted esily 1.65 0.92 2.96 1.51 0.84 2.74 I mind sking for help 0.61 0.28 1.36 0.60 0.27 1.33 I consider myself risk tker 0.60 0.32 1.14 0.56 0.30 1.08 Hve high worklod 0.63 0.33 1.22 0.60 0.31 1.16 Must keep eye on things 0.58 0.30 1.09 0.68 0.35 1.32 I like mentl chllenge 0.59 0.24 1.47 0.52 0.20 1.32 Find work emotionlly demnding 0.44 0.26 0.74* 0.44 0.26 0.74* Pln my own work 0.60 0.34 1.07 0.57 0.32 1.03 Good reltionship with supervisor 0.77 0.30 2.00 0.70 0.26 1.82 Feel t home t work 0.86 0.42 1.78 0.82 0.40 1.71 c. Work type Shift work versus non-shift work 2.07 1.17 3.68* 2.64 1.44 4.85* Work over 8 h per dy 0.37 0.21 0.66* 0.42 0.23 0.77* Be on feet >20 min 1.27 0.71 2.25 2.02 1.06 3.86* Crry mterils round 2.76 1.53 4.99 3.18 1.73 5.86* Use stirwys 1.10 0.59 2.04 1.24 0.66 2.33 Work with mchines 1.67 0.98 2.83 2.43 1.35 4.37* d. Driving to work Prk cr fr wy 1.27 0.74 2.19 1.21 0.70 2.11 Commute to work 0.70 0.37 1.30 0.69 0.37 1.30 e. Sfety orienttion Good blnce in sfety tsks 0.86 0.44 1.69 0.81 0.41 1.61 Supervisor gives high priority 0.66 0.25 1.74 0.68 0.26 1.83 I cn report unsfe cts 1.07 0.45 2.53 1.03 0.43 2.47 My supervisor responds 0.68 0.33 1.43 0.68 0.32 1.43 Solutions for sfety problems re 0.72 0.38 1.35 0.64 0.34 1.22 implemented correctly Hve enough time to work sfely 0.72 0.38 1.38 0.72 0.37 1.39 Sufficiently trined for sfety 0.48 0.20 1.16 0.50 0.20 1.22 I receive sufficient trining 0.66 0.25 1.74 0.66 0.24 1.75 Too few observtions to include in the model. *P < 0.05.
Pge 4 of 6 OCCUPATIONAL MEDICINE Tble 3. Helth-relted chrcteristics of the prticipnts in the study nd the OR nd 95% CI, crude nd djusted for sex Chrcteristics Crude OR Crude 95% CI OR djusted for sex 95% CI djusted for sex. Alcohol Drink three or more lcoholic drinks 0.81 0.39 1.69 0.83 0.40 1.74 during the week b. Smoking Never smoked 0.58 0.34 0.96* 0.49 0.29 0.83* Former smoker 1.58 0.91 2.75 1.84 1.04 3.26* Current smoker 1.05 0.44 2.50 1.28 0.52 3.10 c. Exercise Exercise <1 time per week 2.16 1.16 4.04* 1.89 0.99 3.58 Engge in ctivities with blnce 0.66 0.39 1.12 0.73 0.43 1.25 Hve difficulty blncing on one foot 1.71 0.85 3.44 1.70 0.84 3.45 Hve excellent blnce 0.60 0.34 1.06 0.65 0.37 1.16 d. Other Tke multivitmins 0.90 0.53 1.52 0.81 0.47 1.38 Tke clcium 1.09 0.56 2.14 0.90 0.45 1.80 Wer glsses 1.48 0.84 2.61 1.35 0.76 2.41 Wer these most of the dy 1.24 0.48 3.19 1.28 0.49 3.34 Hve difficulty reding smll print 1.00 0.58 1.72 0.93 0.53 1.61 See objects t distnce 0.96 0.57 1.62 0.90 0.53 1.53 Mediction for llergy 0.92 0.41 2.07 0.69 0.29 1.64 Did you slip outside of work? 1.47 0.81 2.66 1.42 0.78 2.59 If slipped did you seek medicl ttention? 10.96 1.91 62.89 306 missing e. Medicl conditions Allergy 1.75 1.03 2.97* 1.77 1.04 3.02* Migrine 2.29 0.89 5.89* 1.93 0.74 5.09 Stomch or bowel disorder 1.68 0.63 4.45 Arthritis 2.39 1.31 4.35* 2.46 1.34 4.52* Asthm 1.29 0.46 3.62 Bck or neck disorder 1.00 0.46 2.16 Wrist elbow shoulder disorder 2.77 1.29 5.94* Depression 3.04 1.26 7.33* 3.09 1.26 7.57* Dibetes 1.79 0.67 4.80 Hert disese 1.10 0.56 2.15 Felt sd >2 weeks per yer 1.62 0.84 3.11 0.56 0.32 1.19 Dizzy 0.45 0.02 8.50 0.90 0.49 1.63 Dibetes 0.96 0.26 3.50 1.00 0.56 1.75 Coordintion 1.38 0.06 34.26 0.95 0.52 1.73 Allergies 1.50 0.90 2.52 1.43 0.84 2.41 Too few observtions to include in the model. *P < 0.05. significntly ssocited with hving reported STF. With regrd to stress-relted fctors, the OR for cses lwys being in hurry nd finding work emotionlly demnding were significntly less thn one. The risk of STF ws >2-fold for shift work, nd being on one s feet >20 min, crrying mterils round nd working with mchines were lso significnt risk fctors for being cse. Working over 8 h per dy, however, ws inversely ssocited with being cse. Items relted to sfety, such s being ble to report unsfe situtions, how well the supervisor dels with sfety issues nd hving enough time to work sfely were not ssocited with cse sttus. In Tble 3, not engging in regulr exercise ws significntly ssocited with STF cse sttus but lcohol intke ws not. Never smokers were significntly less likely to be cse. Fctors relted to vision, such s wering glsses, being ble to see objects t distnce, hving difficulty reding smll print, were not significntly relted to cse sttus. Allergy, rthritis nd depression (OR = 3.09, 95% CI: 1.26 7.57) were ll sttisticlly significntly ssocited with cse sttus. Tble 4 shows four models produced by multiple logistic regression nlysis. Fctors tht were sttisticlly significntly ssocited with STF in the full model were sex, BMI, crrying mterils, hving rthritis nd lck of exercise. Fctors ssocited with reduced risk of STF were yers of service, working over 8 hours per dy nd never hving smoked.
G. SWAEN ET AL.: SLIPS, TRIPS AND FALLS Pge 5 of 6 Tble 4. OR nd 95% confidence limits from multiple logistic regression nlysis Vrible OR 95% confidence limit 1. Generl model (missing 34 observtions) Femle 2.33* 1.26 4.31 Yers of service 0.54* 0.37 0.79 BMI 1.52* 1.13 2.04 2. Generl model with work-relted fctors (missing 63 observtions) Femle 2.06* 1.02 4.17 Yers of service 0.56* 0.37 0.85 BMI 1.66* 1.19 2.29 Work over 8 h per dy 0.39* 0.19 0.79 Crry mterils round 3.19* 1.53 6.63 3. Generl model with helth-relted fctors (missing 34 observtions) Femle 2.16* 1.12 4.16 Yers of service 0.47* 0.32 0.70 Never smoke 0.43* 0.23 0.80 No exercise (versus ny) 2.32* 1.12 4.83 Arthritis 2.95* 1.52 5.72 4. Full model (missing 48 observtions) Femle 2.46* 1.17 5.19 Yers of service 0.53* 0.34 0.81 BMI 1.44* 1.03 2.02 Work over 8 h per dy 0.42* 0.20 0.88 Crry mterils round 3.01* 1.41 6.43 Arthritis 2.11* 1.01 4.37 Never smoke 0.48* 0.24 0.95 No exercise 2.25* 1.01 5.05 *P < 0.05. Discussion We found the following fctors to be significntly ssocited with reporting STF: femle sex, high BMI, crrying mterils, hving rthritis nd lck of exercise. We found tht long service, working over 8 h per dy nd never hving smoked were significntly ssocited with reduced risk of STF. Other fctors, such s job stress nd eyesight problems were not significntly ssocited with incresed risk. A strength of this study ws the cse control design, which is better design thn the typicl root cuse n lysis for ssessing the cuses of STF. The cse control design llowed us to exmine severl risk fctors simultneously to find the most importnt predictors of STF. However, wekness of our study ws the smll numbers of reported STFs. For this reson, we were unble to evlute risk fctors by severity of the injury. Another limittion ws tht medicl informtion ws insufficiently comprehensive for ll prticipnts to exmine medictions or some pre-existing conditions. Also, in our modelling of the fctors relted to STF, mny vribles were often missing, mking it difficult to drw inferences when ll fctors were exmined t the sme time. Also in some of the cses 2 yers my hve pssed between the STF event nd the time of the survey. Helth- nd work-relted fctors my hve chnged during this time. Such chnges could led to misclssifiction nd thus bis our results. The compny where the study took plce hs extensive sfety progrms to eliminte unsfe situtions nd to trin employees in sfer work prctices. We found tht workers with more experience re better ble to void STF, providing evidence of the effectiveness of these progrms. The compny lso provides periodic medicl exmintions of ll employees nd encourges employees to sty fit nd physiclly ctive through medicl progrms nd exercise fcilities t ech site. Clinicins nd policymkers should consider helth nd fitness progrms s n importnt ddition to trditionl sfety progrms to reduce STF. Future studies should further explore the impct of fitness nd helth sttus on STF nd other workplce injuries. Key points Most reported cses of slips, trips nd flls were minor nd occurred in non-production res. Stying fit nd helthy ws n importnt fctor in reducing risk. Helth nd fitness progrms my be n importnt ddition to trditionl sfety progrms to reduce slips, trips nd flls nd my lso reduce risk from other workplce injuries. Conflicts of interest None declred. References 1. Ntionl Institute for Occuptionl Sfety nd Helth, Worker Deths by Fll: A Summry of Surveillnce Findings nd Investigtive Cse Reports. Cincinnti, OH: US Deprtment of Helth nd Humn Services, NIOSH, 2000. 2. Yoon HY, Lockhrt TE. Nonftl occuptionl injuries ssocited with slips nd flls in the United Sttes. Int J Ind Ergon 2006;36:83 92. 3. Amndus H, Bell J, Tiesmn H, Biddle E. The epidemiology of slips, trips, nd flls in helicopter mnufcturing plnt. Hum Fctors 2012;54:387 395. 4. Snti KA, Ydeqrfr G, Nghvi SH et l. Occuptionl injuries in synthetic fibre fctory in Irn. Occup Med (Lond) 2009;59:62 65. 5. Holcroft CA, Punnett L. Work environment risk fctors for injuries in wood processing. J Sfety Res 2009;40:247 255. 6. Tiwo OA, Cntley LF, Slde MD et l. Sex differences in injury ptterns mong workers in hevy mnufcturing. Am J Epidemiol 2009;169:161 166.
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