The reverse total shoulder replacement (rTSR) has excellent clinical outcomes and prosthesis longevity, and thus, the indications have expanded to a younger age group. The use of a stemless humeral implant has been established in the anatomic TSR; and it is postulated to be safe to use in rTSR, whilst saving humeral bone stock for younger patients. The Lima stemless rTSR is a relatively new implant, with only one paper published on its outcomes. This is a single-surgeon retrospective matched case control study to assess short term outcomes of primary stemless Lima SMR rTSR with 3D planning and Image Derived Instrumentation (IDI), in comparison to a matched case group with a primary stemmed Lima SMR rTSR with 3D planning and IDI. Outcomes assessed: ROM, satisfaction score, PROMs, pain scores; and plain radiographs for loosening, loss of position, notching. Complications will be collated. Patients with at least 1 year of follow-up will be assessed. With comparing the early radiographic and clinical outcomes of the stemless rTSR to a similar patient the standard rTSR, we can assess emerging trends or complications of this new device. 41 pairs of stemless and standard rTSRs have been matched, with 1- and 2-year follow up data. Data is currently being collated. Our hypothesis is that there is no clinical or radiographical difference between the Lima stemless rTSR and the traditional Lima stemmed rTSR

Objectives. A single degenerate intervertebral disc is suggested to promote rapid degeneration in its adjacent discs. We validated this hypothesis using discordant co-twin case-control design. Methods. 185 pairs of twins were selected from the TwinsUK database having cervical MRI scans at baseline and at follow-up, after 10 years. Isolated disc degeneration (IDD) was diagnosed in subjects having severe loss in disc height (graded 3/3) in a single disc, whilst discs immediately adjacent manifested little or no degeneration (graded 0 or 1). The controls' ‘adjacent discs’ were considered at the same levels as their affected co-twins. Results. Eight twin pairs fulfilled case/control criteria. At follow-up, no significant difference in adjacent disc degeneration between IDD cases and controls remained (p=0.69). Conclusions. Using a highly matched case-control design we did not find evidence that lone IDD has an adverse effect on the natural rate of adjacent disc degeneration in the cervical spine. No conflicts of interest. Acknowledgements. This study was supported by a grant from Globus Inc. Arthritis Research UK supported the imaging costs. TwinsUK. The study was funded by the Wellcome Trust; European Community's Seventh Framework Programme (FP7/2007–2013). The study also receives support from the National Institute for Health Research (NIHR)- funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust in partnership with King's College London

Mechanical irritation or impingement of the iliopsoas tendon accounts for 2–6% of persistent postoperative pain cases after total hip arthroplasty (THA). The most common trigger is anterior cup overhang. CT-scan can be used to identify and measure this overhang; however, no threshold exists for symptomatic anterior iliopsoas impingement. We conducted a case–control study in which CT-scan was used to define a threshold that differentiates patients with iliopsoas impingement from asymptomatic patients after THA.

We analyzed the CT-scans of 622 patients (758 CT-scans) between 2011 and 2020. Out of this population we identified 136 patients with symptoms suggestive of iliopsoas impingement. Among them, 6 were subsequently excluded: three because the diagnosis was reestablished intra-operatively (one metallosis, two anterior instability related to posterior prosthetic impingement) and three because they had another obvious cause of impingement (one protruding screw, one protruding cement plug, one stem collar), leaving 130 patients in the study (impingement) group. They were matched to a control group of 138 patients who were asymptomatic after THA. The anterior cup overhang (anterior margin of cup not covered by anterior wall) was measured by an observer (without knowledge of the clinical status) on an axial CT slice based on anatomical landmarks (orthogonal to pelvic axis).

The impingement group had a median overhang of 8 mm [IQR: 5 to 11] versus 0 mm [IQR: 0 to 4] for the control group (p<.001). Using ROC curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%, PPV = 75%, NPV = 85%).

Pain after THA related to iliopsoas impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of iliopsoas irritation or another reason for the pain after THA before concluding impingement is present.

Degenerative hip and spine pathologies often co-exist, as Hip-Spine-Syndrome (HSS). Many patients eventually need surgery in both hip (THR) and spine [decompression-spinal-arthrodesis (DSA)]. This case-control study aims to determine whether the presence of a DSA compromised THR outcome and whether outcome of THR is better if performed prior to- (THR-1. st. ) or after- DSA (THR-2. nd. ). This is a single centre, multi-surgeon, retrospective, case-control study. Of the 748 patients that underwent DSA between 2004–15, 43 patients (54 THRs) have also had a 1° THR(s) at our unit and formed the cases. Thirty-two THRs were performed prior to the DSA (THR-1. st. ) and 22 were done following the DSA (THR-2. nd. ). Most cases had either 1- (n=3) or 2-level (n=20) DSA. The most common DSA level was L4/5 (n=23). The mean THR-DSA interval was 3.6 years. Controls were patients (n=67) without DSA or previous spinal surgery, that had a THR in our unit over the same study period matched for age, gender and type of THR implanted. Patient Reported Outcome Measures (PROMs) were obtained using the Oxford-Hip- and Harris-Hip-Scores (OHS/HHS), with the difference between post- and pre-operative scores defined as Δ. Outcome was compared between Cases and Controls and between THR-1. st. and THR-2. nd. Groups. Outcome measures included complications, revisions, PROMs and cup orientations achieved. The mean age at THR was 67 years old (SD: 11) and most patients were female (n=82, 68%). The mean cup inclination and anteversion angles were 41° (SD:8) and 21° (SD:8). At a mean follow-up of 6 years, the OHS improved from OHS. pre. :16 (SD: 7) to OHS. fu. :41 (SD:10) and the HHS improved from HHS. pre. :51 (SD:14) to HHS. fu. :88 (SD:13). A greater incidence of complications were seen in the Cases (n=10; ARMD-3, infection-4, loosening-2, dislocation-1) compared to the Controls (n=3; dislocation-2, loosening-1) (p=0.01). Consequently, more THRs required revision in the Cases (n=7) compared to the Controls (n=1) (p=0.01). There were no differences in OHS. pre. /OHS. fu. /ΔOHS/HHS. pre. /HHS. fu. /ΔHHS between cases and controls (p=0.1 – 0.9). There were no difference in complications (7/29 Vs. 3/25; p=0.3), nor revision rates (5/29 Vs. 2/25; p=0.3) between THA-1. st. and THA-2. nd. Groups. Greater differences in PROMs were detected between the groups. The THA-1. st. Group, compared to the THA-2. nd. Group had higher OHS. pre. (19 Vs 12), HHS. pre. (54 Vs 48), OHS. fu. (43 Vs 32) and HHS. fu. (93 Vs 76), (p=0.001–0.005). However, no statistically significant difference in ΔOHS (24 Vs 17) and ΔHHS (39 Vs 26) were seen between the THA-1. st. and THA-2. nd. Groups (p=0.1). Patients with a 1° THR and DSA, had a greater rate complications and revisions compared to a matched control. Overall, no difference in PROMs were seen between Cases and Controls. No significantly increased risk of dislocation was seen in this predominantly 1- and 2-level DSA cohort. The superior PROMs detected in the THA-1. st. Group provide evidence that the hip pathology should be addressed 1. st. (in cases with 1- or 2-level planned DSA)

Background:. The rising number of morbidly obese patients may have significant consequences on the health care system. It may alter the effectiveness, safety as well as cost of certain surgical procedures. Reverse shoulder arthroplasty (RSA) is rapidly gaining in popularity. We investigated the effect of morbid obesity on outcomes, complications, disposition and cost in morbidly obese patients undergoing RSA in a 1: 3 case control series. Methods:. Our joint registry was searched for all patients undergoing primary RSA (excluding fractures) with a minimum of 24 months follow-up from 2003–2010; 21 patients with Body Mass Index (BMI) > 35 were identified (follow-up 45 ± 16 months, 17 females and 4 males, age 69 ± 7) and compared to 63 matched control patients with BMI<30 (follow-up 48 ± 20, 50 females, age 71 ± 6). Outcome data was obtained pre- and postoperatively. Patients' Charlson-Deyo comorbidity index (CDI), total comorbidities, operative time, blood loss (EBL), hospitalization length, disposition, cost and complications were recorded. Results:. There were significant (p < 0.05 for all) and comparable improvements in clinical outcomes, i.e. ASES 32→69 versus 40→78) and range-of-motion (i.e. elevation 61°→140° versus 74°→153°). Obese patients had less notching (1/21 versus 5/63, p = 0.007). Obese patients had more total comorbidities excluding obesity (6 versus 4, p = 0.001), higher CDI (2 versus 1, p = 0.025) and higher rates of obstructive sleep apnea (48% versus 3%, p = 0.0001). They had longer operative time by 13 minutes (p = 0.014) and higher EBL by 40 ml (p = 0.008). Length of stay was similar (3.1 versus 2.6 days, p = 0.21) but a 6-fold higher rate of discharge to facilities (6/21 versus 3/63, p = 0.007) and a higher readmission rate (2 versus 0, p = 0.06) was seen in obese patients. Hospital cost was higher by $2,958.00 (p = 0.02). Major (n = 4 versus 8) and minor complication rates (n = 3 versus 14) were similar (p = 0.479 and 0.440, respectively). No intraoperative complications or mechanical device failures were noted in either group. Conclusions:. RSA was as safe and effective in morbidly obese patients, but an increased cost, disposition to facilities and needs after discharge was observed

Introduction. The usefulness of minimal invasive hip replacement is frequently discussed but there is a lack of data on the effect of the surgical approach on early results. We wanted to study the effect of the surgical approach on the peri- and early postoperative outcome. Material/Methods. In a prospective case control study 315 elective hip replacements were performed between January 2008 and March 2010. Until March 2009 a lateral transgluteal approach (STD) was used, then the approach was changed to a minimal invasive anterior approach (MIS). All operations were performed in the same routine setting not affected by the approach. Duration of operation, complications and bloodloss were assessed. 1 week postoperatively, independent mobility, stairs, central analgetics were analysed and length of stay was recorded. At 6 and 12 weeks, pain and patients satisfaction (VAS) and the Harris Hip Score were assessed. Pre- and postoperative radiographs were compared for component position and orientation (EBRA). Results. 6 patients (hips) refused participation, 4 were excluded for other reasons. 174 (57%) hips belonged to STD and 131 (43%) to MIS. There were no demographic differences between both groups. Operation time was longer for MIS (109 vs. 123 min, p=.001). At 1 week, MIS patients were more mobile (rising up from bed, p=.009; stairs, p=.015) and time of hospitalisation became shorter (p=.001). At 6 weeks, MIS patients had less pain at motion (p=.013), less limb (p=.001), a higher HHS (p=.007) and were more satisfied (p=.046). The differences remained unchanged after 12 weeks. There was no difference in implant positioning between the groups. Inclination was higher in group MIS [39° (SD 6°) vs. 38° (SD 7°), p=.030], anteversion was lower [21° (SD 8°) vs. 24° (SD 8°), p=.010]. Conclusion. The introduction of the MIS anterior approach was safe. Early rehabilitation was facilitated and clinical results were better. Radiographical results were not impaired by the new approach. We see no disadvantage of the MIS anterior approach. Adaptions in the clinical setup might further facilitate rehabilitation

Aim

Cutibacterium acnes is a significant cause of late-onset spinal implant infection (SII). In addition, usual preoperative prophylactic measures may be insufficient to prevent C. acnes operating site colonisation and infection, as demonstrated for prosthetic shoulder surgery. However, little information is available regarding risk factors for SII due to this microorganism. The aims of this study were to determine the characteristics of and risk factors for C. acnes SII.

Introduction

The alternative kinematic alignment (KA) technique for total knee arthroplasty (TKA) aims at restoring the native joint line orientation and laxity of the knee. The goal is to generate a more physiological prosthetic knee enabling higher functional performance and satisfaction for the patient. KA TKA have only been reported so far with cruciate retaining and posterior-stabilised designs. Similarly, medial pivot design for TKA has been recently developed to enable more natural knee kinematics and antero-posterior stability. The superiority of KA technique and medial pivot implant design is still controversial when compared to current practice. Our study aims to assess the value of KA TKA when performed with medial pivot implants.

Introduction: Infection after hip or knee replacement occurs with low frequency but shares high morbidity. Aim of this study was an evaluation of incidence and risk factors related to post operative infection after joint lower limb joint replacement in an orthopaedics unit. Material and methods: This is a monocentric, retrospective, case control study over the years 2000 to 2002. All first intention Total Hip and Knee Replacement and revision cases for mechanical reasons that became infected were identified. Demographic, surgical and medical variables, potentially associated to prosthetic infection were compared for these patients to a control group of non ifected patients over the same time, matched for sex, age and surgery type. Results: Ten patients, all male, contracted post operative joint infection, out of 630 Total Hip or Knee Arthroplasties. This represented 1.2% after hip replacement and 3.1% after knee replacement. Bacteriological datas showed a majority of Staphylococal infection (5 aureus, 1 epidermidis), 2 among these being resistant to meticillin, but also evidence of ENT commensals (2 Streptococci milleri, 1 Actinomyces) and one epidermal commensal (Propionobacterium acnes). Univariate analysis: datas associated with increased risk of infection were diabetes melitus (OR 9.3; CI 95% 1.4–63), operating time exceeding 120 minutes (OR15.5 ; CI 95% 1,73–139,66), superficial wound infection (odds ratio 29; CI95% 2,77–303,32), coinfection outside the operation site (urinary tract , dental infection) (OR: 9,3 ; CI 95% 1,33–63,2). In our study an MNIS score higher than 1, autologous transfusion, locore-gional anaesthesia with or without the use of a catheter, antibioprophylaxis that did not comply with national recommendations could not be drawn as a risk factor. Discussion: Incidence of infection and risk factors related to infection in our study were found similar tothe results of published datas. The small number of events (10 cases) did not allow us to realize multivariate analysis and could explain that some known risk factors such as non recommended antibioprophylaxis, could not be elicitated. However these results suggested the need to reevaluate the system of prevention of infection in our centre such as protocolization of antibioprophylaxis and screening for and treatement of perioperative coinfection

We aim to determine the differences in lower limb joint kinematics during the golf swing of patients who had undergone Total Knee Arthroplasty (TKA) and a control group of native knee golfers.

A case-control study was undertaken with ten golfers who had undergone TKA (cruciate retaining single radius implant) and five age and matched golfers with native knees. Each golfer performed five swings with a driver whilst being recorded at 200Hz by a ten-camera motion capture system. Knee and hip three-dimensional joint angles (JA) and joint angular velocities (JAV) were calculated and statistically compared between the groups at six swing events.

The only significant differences in knee joint kinematics between TKA and control groups was a lower external rotation JA in the left knee during the backswing (p=0.010). There was no significant difference in knee JAV between the groups. Both hips demonstrated significantly (p=0.023 for left and p=0.037 for right) lower flexion in the TKA group during the takeaway swing event, and there was lower internal rotation in the backswing and greater external rotation in the downswing of the right hip. There was also slower left hip extension JAV in the downswing.

Normal knee kinematics were observed during the golf swing following TKA, with the exception of reduced external rotation in the left knee during the back swing and the right during the down swing. The differences demonstrated in the hip motion indicate that they may make compensatory movements to adjust to the reduced external rotation demonstrated in the knee.

There is a lack of information about the association between patellofemoral osteoarthritis (PFOA) and both adolescent Anterior Knee Pain (AKP) and previous patellar dislocations.

This case-control study involved 222 participants from our knee arthroplasty database answering a questionnaire. 111 patients suffering PFOA were 1:1 matched with a unicompartmental tibiofemoral arthritis control group. Multivariate correlation and binary logistic regression analysis was performed, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated. This analysis helps us assess the effect of both variables whilst adjusting for major confounders, such as previous surgery and patient-reported instability.

An individual is 7.5 times more likely to develop PFOA if they have suffered adolescent AKP (OR 7.5, 95% CIs 1.51–36.94). Additionally, experiencing a patellar dislocation increases the likelihood of development of PFOA, with an adjusted odds ratio of 3.2 (95% CIs 1.25–8.18). A 44-year difference in median age of first dislocation was also observed between the groups.

This should bring into question the traditional belief that adolescent anterior knee pain is a benign pathology. Patellar dislocation is also a significant risk factor. These patients merit investigation, we encourage clinical acknowledgement of the potential consequences when encountering patients suffering from anterior knee pain or patellar dislocation.

Introduction

Increasingly young and active patients are concerned about revision arthroplasty forcing the manufacturers to think about revision prostheses that fit to this population while meeting the indications and fitting with bone losses and ligament deficiencies. One of those industrials claims that its system allows the surgeon to rise the constraint from a posterior stabilized (PS) prostheses to a semi-constraint total stabilized (TS) prostheses without modifying the gait pattern thanks to a similar single radius design. The aim of the study was to compare gait parameters in patients receiving either PS or TS knee prostheses.

Objective

The relationship between the index (2D) to ring finger (4D) is one of the most commonly studied anthropometric measures, which is believed to offer insight into early growth and the foetal environment. This study aimed to determine the relationship between the 2D:4D ratio and the risk of Perthes' disease in children.

Introduction

Acetabular dysplasia is associated with an increased risk of hip pain and early development of osteoarthritis (OA). The Bernese peri-acetabular osteotomy (PAO) is the most well-established technique in the Western world for the treatment of symptomatic acetabular dysplasia. This case-control study aims to assess whether the severity of acetabular dysplasia has an effect on outcome following Peri-Acetabular Osteotomy (PAO) and/or the ability to achieve desired acetabular correction.

The aim of this study was to compare the long-term outcome from total knee replacement (TKR) in young versus old patients in terms of pain and functional outcome.

We used our arthroplasty database which recorded prospectively pain and American Knee Society scores at regular intervals over ten years after TKR. The procedures used a modern, cemented resurfacing type cruciate retaining prosthesis. A cohort of young patients (< 55 years) were identified. A control group of patients ≥ 56 was identified, matching for ASA, body mass index and underlying condition. Change over time was analysed using a factorial repeated measures ANOVA test, which allowed for investigation of difference between groups.

40 Knees in 26 patients were identified. 2 patients died prior to follow up, 2 were revised within the study period. (1 for infection at 2 years and one for change of poly at 7 years) and a further 4 were lost to follow up. 7 knees could not be matched and were excluded. This left a study group of 24 young and 24 older knees.

Pain scores (p=0.025) and American Knee Society “Knee” (p<0.001) and “Function” (p<0.001) scores changed significantly over time. There were however no statistical differences over the 10 year period in pain (p=0.436) and knee performance (0.618) but overall function was higher throughout the period in the younger group (=0.004).

Knee replacement in younger patients produces similar outcomes in terms of pain and function compared with older patients and TKR should not be withheld purely on account of age.

The aim of this study was to compare the long-term outcome from total knee replacement (TKR) in young versus old patients in terms of pain and functional outcome.

We used our arthroplasty database which recorded prospectively pain and American Knee Society scores at regular intervals over ten years after TKR. The procedures used a modern, cemented resurfacing type cruciate retaining prosthesis. A cohort of young patients (≤55 years) were identified. A control group of patients > 56 was identified, matching for ASA, body mass index and underlying condition. Change over time was analysed using a factorial repeated measures ANOVA test, which allowed for investigation of difference between groups.

40 Knees in 26 patients were identified. 2 patients died prior to follow up, 2 were revised within the study period. (1 for infection at 2 years and one for change of poly at 7 years) and a further 4 were lost to follow up. 7 knees could not be matched and were excluded. This left a study group of 24 young and 24 older knees.

Pain scores (p=0.025) and American Knee Society “Knee” (p<0.001) and “Function” (p<0.001) scores changed significantly over time. There were however no statistical differences over the 10 year period in pain (p=0.436) and knee performance (0.618) but overall function was higher throughout the period in the younger group (=0.004).

Knee replacement in younger patients produces similar outcomes in terms of pain and function compared with older patients and TKR should not be withheld purely on account of age.

Purpose: To determine, the foot pressure pattern in ankle osteoarthritis before and after ankle fusion. To compare the results with those of normal individuals. Method: The distribution of plantar pressures of the foot has been measured by different means ranging from crude methods to modern techniques using transducers in the form of mats and insole devices. A less cumbersome in-sole transducer called FSCAN sensor has become commercially available. This device has been used to measure dynamic pressures at the Shoe-Foot interface in normal people and in pathological conditions in the foot. However the pressure distribution in the soles of patients with ankle osteoarthritis has not been studied. We present a prospective case control study of 18 participants (9 with ankle osteoarthritis and 9 controls). Ethical approval was obtained for this study. The controls were matched to cases by foot shape, gender and weight. The pressure measurement device, technique of ankle fusion and post operative protocol (for the arthritis patients) were standardised for all the participants. The Ankle-Hindfoot Scale and SF-36 Health Survey scores were obtained pre-operatively and at six months post-operatively and compared. Results: There were four females and 14 males. The average age was 67 years. The forefoot in patients with arthritis bore more weight compared to controls and this was statistically significant (P< 0.05). The forefoot pressure was also higher than the hind foot pressure in the patients, both preoperatively and post operatively. This was also statistically significant, (P< 0.05). The Ankle-Hindfoot Scale improved significantly postoperative, (P< 0.05). There was no statistically significant difference in the SF-36 Health Survey scores. Conclusion: The study shows that ankle osteoarthritis changes the pressure distribution in the foot, with preponderance in the forefoot. It also shows that after ankle fusion there is a change in the pressure. However, the forefoot still bears more pressure compared to the hind foot. The result may help in predicting areas of the foot at risk in developing problems due to high pressure load post ankle fusion. It may also help in designing foot orthosis in the peri-operative management of the foot in ankle osteoarthritis

A Prosthetic Joint infection (PJI) is an orthopedic disaster. There is a direct correlation between persistent wound drainage (>72 hours) and the development of a PJI. It is unknown if early wound drainage (<12 hours) is correlated with PJI.

We included 753 consecutive patients treated with a Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) operated between December 2012 and December 2013. All patients were treated according to our local fast track joint surgery protocol. We retrospectively analyzed the prospectively collected data on wound drainage and PJI.

The diagnosis PJI was established according to the definition by the International Consensus Group on Prosthetic Joint Infections. Per PJI-case, two control-cases were matched on type of surgery (THA or TKA) and day of surgery. Analysed variables were co-morbidities, medication, use of drains, haematoma, wound drainage and dressing changes. Statistical analysis was done using Kaplan Meier logistic regression with statistic significance set at p<0.005.

In 753 included patients, 25 PJI-cases were identified and 50 controls were matched. Cases had significant more wound drainage (88% vs 36% P=0.001)) and wound dressing changes (56% vs 18% P=0.006) in the direct postoperative phase (<12 uur postoperative). Cases had more haematoma (44% vs 10% P=0.005). We found no association between PJI and co-morbidity, medication and use of drains.

We found that wound drainage directly postoperative (<12hr) correlated with PJI. We believe that direct post operative drainage is of crucial importance in the development of PJI and inhibition of drainage offers opportunities for prevention of PJI. The use of tranexamic acid, suction drains and critical evaluation of guidelines for preventing thrombo embolic events all offer reducing the risk on wound drainage and the development of PJI.

The aim of this study was to compare the long-term outcome from total knee replacement (TKR) in young versus old patients in terms of pain and functional outcome.

We used our arthroplasty database, which recorded prospectively pain and American Knee Society scores at regular intervals over ten years after TKR. The procedures used a modern, cemented resurfacing type cruciate retaining prosthesis. A cohort of young patients (≤55 years) was identified. A control group of patients ≥ 56 was identified, matching for ASA, body mass index and underlying condition. Change over time was analysed using a factorial repeated measures ANOVA test, which allowed for investigation of difference between groups. 40 Knees in 26 patients were identified. 2 patients died prior to follow up, 2 were revised within the study period (1 for infection at 2 years and one for change of poly at 7 years) and a further 4 were lost to follow up. 7 knees could not be matched and were excluded. This left a study group of 24 young and 24 older knees. Pain scores (p=0.025) and American Knee Society “Knee” (p<0.001) and “Function” (p<0.001) scores changed significantly over time. There were however no statistical differences over the 10-year period in pain (p=0.436) and knee performance (0.618) but overall function was higher throughout the period in the younger group (=0.004).

We conclude that Knee replacement in younger patients produces similar outcomes in terms of pain and function compared with older patients and TKR should not be withheld purely on account of age.

Aims

It is well established that there is a strong association between Perthes’ disease and worsening socioeconomic deprivation. It has been suggested that the primary determinant driving this association is exposure to tobacco smoke. This study aimed to examine this hypothesis.