Cognition, mood and quality-of-life outcomes among low literacy adults living with epilepsy in rural Kenya: A preliminary study

Magnetic resonance imaging findings in Kenyans and South Africans with active convulsive epilepsy: An observational study

OBJECTIVE

Focal epilepsy is common in low- and middle-income countries. The frequency and nature of possible underlying structural brain abnormalities have, however, not been fully assessed.

METHODS

We evaluated the possible structural causes of epilepsy in 331 people with epilepsy (240 from Kenya and 91 from South Africa) identified from community surveys of active convulsive epilepsy. Magnetic resonance imaging (MRI) scans were acquired on 1.5-Tesla scanners to determine the frequency and nature of any underlying lesions. We estimated the prevalence of these abnormalities using Bayesian priors (from an earlier pilot study) and observed data (from this study). We used a mixed-effect modified Poisson regression approach with the site as a random effect to determine the clinical features associated with neuropathology.

RESULTS

MRI abnormalities were found in 140 of 240 (modeled prevalence = 59%, 95% confidence interval [CI]: 53%-64%) of people with epilepsy in Kenya, and in 62 of 91 (modeled prevalence = 65%, 95% CI: 57%-73%) in South Africa, with a pooled modeled prevalence of 61% (95% CI: 56%-66%). Abnormalities were common in those with a history of adverse perinatal events (15/23 [65%, 95% CI: 43%-84%]), exposure to parasitic infections (83/120 [69%, 95% CI: 60%-77%]) and focal electroencephalographic features (97/142 [68%, 95% CI: 60%-76%]), but less frequent in individuals with generalized electroencephalographic features (44/99 [44%, 95% CI: 34%-55%]). Most abnormalities were potentially epileptogenic (167/202, 82%), of which mesial temporal sclerosis (43%) and gliosis (34%) were the most frequent. Abnormalities were associated with co-occurrence of generalized non-convulsive seizures (relative risk [RR] = 1.12, 95% CI: 1.04-1.25), lack of family history of seizures (RR = 0.91, 0.86-0.96), convulsive status epilepticus (RR = 1.14, 1.08-1.21), frequent seizures (RR = 1.12, 1.04-1.20), and reported use of anti-seizure medication (RR = 1.22, 1.18-1.26).

SIGNIFICANCE

MRI identified pathologies are common in people with epilepsy in Kenya and South Africa. Mesial temporal sclerosis, the most common abnormality, may be amenable to surgical correction. MRI may have a diagnostic value in rural Africa, but future longitudinal studies should examine the prognostic role.

Determinants of quality of life in Nigerian female patients with epilepsy on carbamazepine and levetiracetam monotherapy

Background

The study is aimed to identify the predictors of Quality of Life (QOL) in women with epilepsy (WWE) on carbamazepine (CBM) and levetiracetam (LTM) monotherapy. 100 WWE were recruited (50 each on CBM and LTM), after clinical diagnosis of epilepsy supported by Electroencephalography (EEG) features and seizures classification by 2017 International League Against Epilepsy (ILAE) criteria, the Quality of Life Inventory Scale 31(QOLIE-31) and Zung Self-Rating Depression Scale (ZSRDS) were used to assess QOL and depression, respectively.

Result

Higher QOLIE-31 scores was seen in the LTM group across all domains except seizure worry (p = 0.051) compared to CBM group. Logistic regression showed that the use of CBM (p = 0.000), fast frequency on EEG (p = 0.005), longer duration of epilepsy (p = 0.017), presence of depression (p = 0.008) and lower level of education (p = 0.003) were predictors of QOL. Progesterone (p = 0.040), oestradiol (p = 0.011) and prolactin (p = 0.002) in follicular phase showed significant association with QOLIE-total score. In the luteal phase, luteinizing hormone–follicle stimulating hormone (LH–FSH) ratio (p = 0.009) and testosterone (p = 0.015), FSH (p = 0.015), prolactin (p = 0.000), showed significant association with QOL. None of the hormones independently predicts QOL.

Conclusion

LTM group appears to have better QOL than CBM group. Healthcare providers should focus on addressing these identified predictors which include medication effect, depression, Level of education, EEG background and duration of epilepsy with aim of improving QOL.

Co-morbid mental health conditions in people with epilepsy and association with quality of life in low- and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Comorbid mental health conditions are common in people with epilepsy and have a significant negative impact on important epilepsy outcomes, although the evidence is mostly from high-income countries. This systematic review aimed to synthesise evidence on the association between comorbid mental health conditions and quality of life and functioning among people with epilepsy living in low- and middle income countries (LMICs).

METHODS

We searched PubMed, EMBASE, CINAHL, Global Index medicus (GID) and PsycINFO databases from their dates of inception to January 2022. Only quantiative observational studies were included. Meta-analysis was conducted for studies that reported the same kind of quality of life and functioning outcome. Cohen's d was calculated from the mean difference in quality-of-life score between people with epilepsy who did and did not have a comorbid depression or anxiety condition. The protocol was registered with PROSPERO: CRD42020161487.

RESULTS

The search strategy identified a total of 2,101 articles, from which 33 full text articles were included. Depression was the most common comorbid mental health condition (33 studies), followed by anxiety (16 studies). Meta-analysis was conducted on 19 studies reporting quality of life measured with the same instrument. A large standardized mean effect size (ES) in quality of life score was found (pooled ES = -1.16, 95% confidence interval (CI) - 1.70, - 0.63) between those participants with comorbid depression compared to non-depressed participants. There was significant heterogeneity between studies (I2 = 97.6%, p < 0.001). The median ES (IQR) was - 1.20 (- 1.40, (- 0.64)). An intermediate standard effect size for anxiety on quality of life was also observed (pooled ES = -0.64, 95% CI - 1.14, - 0.13). There was only one study reporting on functioning in relation to comorbid mental health conditions.

CONCLUSION

Comorbid depression in people with epilepsy in LMICs is associated with poor quality of life although this evidence is based on highly heterogeneous studies. These findings support calls to integrate mental health care into services for people with epilepsy in LMICs. Future studies should use prospective designs in which the change in quality of life in relation to mental health or public health interventions across time can be measured.

Correlates of health-related quality of life in primary caregivers of perinatally HIV infected and HIV exposed uninfected adolescents at the Kenyan Coast

BACKGROUND

Mothers and other primary caregivers play a crucial role in looking after perinatally HIV infected, and HIV exposed uninfected adolescents in sub-Saharan Africa. Day- to-day caregiving in the context of limited instrumental support and added biomedical risk (HIV seropositivity) may expose these caregivers to adverse states of health. Unfortunately, very few studies have examined their health-related quality of life (HRQoL). Our study documents the HRQoL profile, and associated factors in primary caregivers of perinatally HIV infected, perinatally HIV exposed but uninfected and HIV unexposed/uninfected adolescents aged 12-17 years at the Kenyan Coast.

METHODS

This was a cross-sectional analysis of 485 primary caregivers: 195 of perinatally HIV infected adolescents, 128 of perinatally HIV exposed but uninfected adolescents and 162 of HIV unexposed/uninfected adolescents. All caregivers completed a self-report measure of HRQoL (having 8 subscales), depressive symptoms, and parenting stress. They also provided their sociodemographic information and that of the care recipients. We used one-way analysis of variance to assess statistical differences among the groups. Linear regression analyses were used to identify correlates of HRQoL.

RESULTS

Overall, caregivers of HIV unexposed/uninfected adolescents reported significantly higher mean HRQoL scores than the other caregivers in the overall HRQoL domain and majority of the subscales. There were no statistical differences in the overall HRQoL scores and most subscales between caregivers of HIV exposed adolescents. Linear regression analyses across the sample indicated that depressive symptoms, increasing age of caregiver, and caring for an adolescent perinatally exposed to HIV were significantly associated with reduced HRQoL at both the overall and sub-scale level. Having a professional job relative to subsistence farming was the only factor associated with improved overall HRQoL. At subscale level, higher socioeconomic status correlated positively with HRQoL while being a grandparent, level of education, parenting stress were negatively associated with HRQoL.

CONCLUSIONS

Caregivers in this sample, especially those who are ageing, at risk of mental ill-health, and taking care of adolescents perinatally exposed to HIV, appear to be vulnerable to poor quality of life. Inclusive and multi-component interventions tailored to the caregivers' psychosocial and mental needs will potentially enhance their quality of life.

High prevalence of epilepsy in Northern Rwanda: Exploring gender differences

INTRODUCTION

In sub-Saharan Africa (SSA), the prevalence of lifetime epilepsy varies widely between subregions and is higher in rural compared to urban regions. Observed versus expected numbers of patients with epilepsy (PwE) in the northern province of Rwanda did not match the prevalence of 49‰ reported in 2005 in Rwanda. We report a confirmatory prevalence study focused on gender-specific observations.

METHODS

A cross-sectional door-to-door approach was used in three rural villages. First, epilepsy screening using the Kinyarwanda version of the Limoges questionnaire was performed. Second, confirmation of epilepsy diagnosis was completed by trained physicians.

RESULTS

In total, 2681 persons (56.14% female) were screened. Of 168 positively screened, 128 persons were diagnosed with epilepsy confirming the prevalence of lifetime epilepsy of 47.7‰ (CI 39.8-56.8). The diagnosis gap was 62.5% with 80 newly diagnosed. The overall female:male ratio was 1.61:1.00. A male preponderance below 9 years of age inverted to a female preponderance above 20 years of age. Female PwE had an older age at first seizure, reported different reasons for not seeking care, and differed from male PwE in possible etiology. For previously diagnosed PwE, the treatment gap was more than 77%.

CONCLUSION

A high prevalence in rural areas was confirmed, with an observed female/male ratio among the highest of published door-to-door surveys in SSA. Gender differences in associated co-morbidities and age at first seizure warrant future research of underlying etiologies and possible survival bias. A better understanding and focus on gender-associated care-seeking patterns, education, and specific needs are recommended.

[Cognitive impairment and social functioning in organic personality disorder due to epilepsy]

OBJECTIVE

To develop criteria for the diagnosis of cognitive impairment (CI) and to determine the degree of social functioning in organic personality disorder due to epilepsy.

MATERIAL AND METHODS

One hundred and twenty-six patients with epilepsy, aged 18 to 65 years, with disease duration of 11 to 20 years, were examined. The main research method is clinical-psychopathological. The Mini-mental state examination (MMSE) was administered to assess the severity of CI. The Global Assessment of Functioning (GAF) scale was used to assess social functioning.

RESULTS AND CONCLUSION

The structure of organic personality disorder due to epilepsy is determined by a combination of CI and personality changes with a predominance of explosive (short temper, irritability, brutality, explosiveness) or defensive (passivity, suggestibility, vulnerability, suspiciousness, sensitivity, subordination) traits. CI includes impaired thinking, attention, and memory and is manifested by inertia, stiffness, toughness, rigidity, slowing down the pace of thought processes, as well as difficulty in concentrating, impaired direct and indirect memory. Three groups of patients with mild, moderate and severe CI are isolated. In the group with mild CI, thorough thinking with a slow pace and a decrease in the ability to learn new things, which was com. When assessing impairment of social functioning fa moderate and severe of maladaptation with impairments in all areas of activity is revealed in people with explosive personality characteristics and a mild degree - in people with defensive features. It has been shown that the analysis of cognitive impairment is critical in the diagnosis of organic personality disorder due to epilepsy.

Validation of the Health-Related Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) for Brazilian Portuguese

OBJECTIVE

The present study aimed to validate the 55-item Health-Related Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) in Brazilian Portuguese and evaluate the relation of its results with clinical data and caregiver burden.

METHODS

The QOLCE-55 was submitted to translation, back-translation, and cultural adaptation in a pilot sample with 20 subjects. To ensure the psychometric properties of validation, the validation of the QOLCE-55 was carried out in a sample of 45 patients with epilepsy aged between 4 and 18 years and their parents or caregivers and compared with the results of other quality-of-life instruments, namely, the QVCE-50 and QOLIE-AD-48, as well as with the SDQ, abrief behavioral screeningquestionnaire. The WASI and SON-R 2½-7 [a] were used for evaluation of intelligence quotient (IQ) and the Burden Interview for the caregiver burden.

RESULTS

Internal consistency measured by Cronbach's alpha coefficient was moderate (0.692; p = 0.264), and the test-retest reliability analyzed by the intraclass correlation coefficient was satisfactory when compared with the results by different examiners on the same day (0.951; p = 0.001) and at different times (0.778; p = 0.001). This version of the QOLCE-55 presented a strong correlation with the QVCE-50 (0.904; p < 0.001) and SDQ (-0.428; p = 0.004) but a low correlation with the QOLIE-AD-48 (0.094; p = 0.729). This version also presented a correlation with IQ (R = 0.456, p = 0.003) and an inverse correlation with the Burden Interview (-0.390; p = 0.012). Low quality of life was associated with the presence of tonic-clonic seizures (p = 0.005), polytherapy (p = 0.003), and low socioeconomic conditions (p = 0.005).

CONCLUSIONS

The Brazilian Portuguese version of the QOLCE-55 was confirmed as a reliable and valid scale to assess quality of life in children and adolescents with epilepsy. Behavioral problems, caregiver burden, tonic-clonic seizures, polytherapy, and socioeconomic precariousness were associated with low quality-of-life values, while IQ was positively correlated with the quality of life in this population.

Therapeutic Targets for the Treatment of Comorbidities Associated with Epilepsy

One of the most common neurological disorders, which occurs among 1% of the population worldwide, is epilepsy. Therapeutic failure is common with epilepsy and nearly about 30% of patients fall in this category. Seizure suppression should not be the only goal while treating epilepsy but associated comorbidities, which can further worsen the condition, should also be considered. Treatment of such comorbidities such as depression, anxiety, cognition, attention deficit hyperactivity disorder and, various other disorders which co-exist with epilepsy or are caused due to epilepsy should also be treated. Novel targets or the existing targets are needed to be explored for the dual mechanism which can suppress both the disease and the comorbidity. New therapeutic targets such as IDO, nNOS, PAR1, NF-κb are being explored for their role in epilepsy and various comorbidities. This review explores recent therapeutic targets for the treatment of comorbidities associated with epilepsy.

Cognitive dysfunction in Nigerian women with epilepsy on carbamazepine and levetiracetam monotherapy

BACKGROUND

This study aims to identify the determinants of cognitive dysfunction and compare the effect of CPZ and LTC on cognition in WWE.

METHODS

An observational study involving 87 consenting adult WWE aged between 16 and 40 years on LTC or CZP monotherapy. At enrollment, an interviewer-based questionnaire was used to obtain demographic and clinical information from participants. The diagnosis of epilepsy was mainly clinical and supported by electroencephalographic (EEG) features and classified based on recommendation by the 2017 International League Against Epilepsy (ILAE). Zung Self-Reporting Depression Scale (ZSRDS) was used to assess the mood of participants. The Community Screening Interview for Dementia (CSID) was used to assess various cognition domains. The National Hospital Seizure Severity Scale (NHS-3) was used to assess disease severity.

RESULTS

There were statistical differences between the CZP and LTC groups in all domains of cognition assessed except for orientation. The total CSID scores of the LTC group were 59.2 (4.9) as opposed to CZP group, 57.2 (5.0); p: .005. Those with focal onset seizures had lower median total CSID score (58; IQR: 54-62) when compared to those with generalized onset seizures (62; IQR: 58-62), p: .012. There was a significant correlation between ZSRD score and NHS-3 score; rho: 0.30, p: .007. Bivariate analysis shows statistically significant correlation between total CSID score and ZSRDS (rho: -0.65), BMI (rho: 0.22), and NHSS-3 score (rho: -0.36), respectively. However, the effect of AED on CSID scores was lost after multivariate quantile regression with only ZSRDS retaining significance.

CONCLUSION

Depression, seizure severity, type and structural etiology were associated with cognitive impairment among WWE. However, on regression model, only depression was statistically significant. The presence of more risks for cognitive impairment in the CZP group limits possible conclusion of LTC superiority.

Quality of life and its associated factors among epileptic patients attending public hospitals in North Wollo Zone, Northeast Ethiopia: A cross-sectional study

BACKGROUND

Epilepsy is thought to be caused by witchcraft, evil spirit, and God's punishment for sins in many developing countries. As a result, people with epilepsy and their families usually suffer from stigma, discrimination, depression, and other psychiatric problems. Thus, this study aimed to assess the quality of life and its associated factors among epileptic patients attending public hospitals in North Wollo Zone, Northeast Ethiopia.

METHODS

An institution-based cross-sectional study design was employed in this study. A simple random sampling technique was utilized. Health-related quality of life was measured based on the total score of the Quality of Life in Epilepsy Inventory (QOLIE-31) instrument. Data were entered into Epi-data 3.1 statistical package and exported to SPSS Version 20 for further analysis. Linear regression models were used to assess the relationship between quality of life and the independent variables. Statistically significant values were declared at a P-value of < 0.05.

RESULTS

A total of 395 patients participated in the study making the response rate 98.5%. The mean age of the participants was 32.39 ±10.71 years. More than half, 199 (50.4%) of epileptic patients had an overall weighted average health related quality of life score of mean and above. Male sex (B = 4.34, 95%CI, 0.41, 8.27, P = 0.03), higher educational status (B = 7.18, 95%CI, 1.39, 13.00, P = 0.015) and age at onset of epilepsy (B = 0.237, 95%CI, 0.02, 0.45, P = 0.035) were associated with increased health related quality of life score. On the other hand, family history of epilepsy (B = -4.78, 95%CI,-9.24,-0.33, P = 0.035), uncontrolled seizure (B = -11.08, 95%CI,-15.11,-7.05, P < 0.001), more than 5 pre-treatment number of seizures (B = -4.86, 95%CI,-8.91,-0.81, P = 0.019), poor drug adherence (B = -11.65, 95%CI,-16.06,-7.23, P < 0.001), having moderate (B = -4.526, 95%CI,-8.59,-0.46, P = 0.029) to sever (B = -12.84, 95%CI,-18.30,-7.37, P < 0.001) anxiety and depression, believing that epilepsy is caused by evil spirit (B = -7.04, 95%CI,-11.46,-2.61, P = 0.002), drinking alcohol (B = -5.42, 95%CI,-10.72,-0.13, P = 0.045), and having other co-morbidities (B = -9.35, 95%CI,-14.35,-4.36, P < 0.001) were significantly negatively associated with the health related quality of life score among epileptic patients.

CONCLUSIONS

Only around half of the epileptic patients have a good health-related quality of life. In addition, multiple variables including family history, uncontrolled seizure, and poor drug adherence were associated with quality of life among epileptic patients. Hence, targeting these variables in epilepsy management is recommended.

Comorbid mental disorders and quality of life of people with epilepsy attending primary health care clinics in rural Ethiopia

BACKGROUND

Evidence from high-income countries demonstrates that co-morbid mental disorders in people with epilepsy adversely affect clinical and social outcomes. However, evidence from low-income countries is lacking. The objective of this study was to measure the association between co-morbid mental disorders and quality of life and functioning in people with epilepsy.

METHODS

A facility-based, community ascertained cross-sectional survey was carried out in selected districts of the Gurage Zone, Southern Ethiopia. Participants were identified in the community and referred to primary health care (PHC) clinics. Those diagnosed by PHC workers were recruited. Co-morbid mental disorders were measured using a standardised, semi-structured clinical interview administered by mental health professionals. The main outcome, quality of life, was measured using the Quality of Life in Epilepsy questionnaire (QOLIE-10p). The secondary outcome, functional disability, was assessed using the 12-item World Health Organization Disability Assessment Schedule (WHODAS-2).

RESULTS

The prevalence of comorbid mental disorders was 13.9%. Comorbid mental disorders were associated with poorer quality of life (Adjusted (Adj.) β -13.27; 95% CI -23.28 to-3.26) and greater disability (multiplier of WHODAS-2 score 1.62; 95% CI 1.05, 2.50) after adjusting for hypothesised confounding factors. Low or very low relative wealth (Adj. β = -12.57, 95% CI -19.94 to-5.20), higher seizure frequency (Adj.β coef. = -1.92, 95% CI -2.83 to -1.02), and poor to intermediate social support (Adj. β coef. = -9.66, 95% CI -16.51 to -2.81) were associated independently with decreased quality of life. Higher seizure frequency (multiplier of WHODAS-2 score 1.11; 95% CI 1.04, 1.19) was associated independently with functional disability.

CONCLUSION

Co-morbid mental disorders were associated with poorer quality of life and impairment, independent of level of seizure control. Integrated and comprehensive psychosocial care is required for better health and social outcomes of people with epilepsy.

The Oscillatory Basis of Working Memory Function and Dysfunction in Epilepsy

Working memory (WM) deficits are pervasive co-morbidities of epilepsy. Although the pathophysiological mechanisms underpinning these impairments remain elusive, it is thought that WM depends on oscillatory interactions within and between nodes of large-scale functional networks. These include the hippocampus and default mode network as well as the prefrontal cortex and frontoparietal central executive network. Here, we review the functional roles of neural oscillations in subserving WM and the putative mechanisms by which epilepsy disrupts normative activity, leading to aberrant oscillatory signatures. We highlight the particular role of interictal epileptic activity, including interictal epileptiform discharges and high frequency oscillations (HFOs) in WM deficits. We also discuss the translational opportunities presented by greater understanding of the oscillatory basis of WM function and dysfunction in epilepsy, including potential targets for neuromodulation.

Depression, sleep quality, and social isolation among people with epilepsy in Bhutan: A cross-sectional study

PURPOSE

The aim of this study was to analyze the possible contributions of seizure burden, sleep quality, and social integration to depression among people with epilepsy (PWE) in Bhutan.

METHODS

Bhutan is a lower-middle-income country in Southeast Asia with a public healthcare system without neurologists. People with epilepsy were prospectively recruited from psychiatrist-run epilepsy clinics at the National Referral Hospital in the capital city of Thimphu. Adult participants with epilepsy were interviewed for clinical history, sleep quality using the Pittsburgh Sleep Quality Index, social networks using the Berkman-Syme Social Network Index, and depressive symptoms using the Patient Health Questionnaire - 9 (PHQ-9). A multivariable regression model was built to assess the relationship between depression as an outcome and the possible contributors of sleep quality, sex, and seizure in the prior month.

RESULTS

Out of 80 participants (39 women, mean age: 29.4 years old, range: 18-56 years, 58 [73%] with a seizure in the previous month), 33% had poor sleep quality, 68% were socially isolated, 30% had a mild depressive symptom burden or more, and 18% reported suicidal ideation at the time of their interview. Women had a higher average PHQ-9 score versus men, which showed a trend towards statistical significance (5.6 versus 3.3 PHQ-9 points, p = 0.07), and on average met criteria for mild depression. Social integration was not significantly associated with sleep quality and had no relationship with depressive burden. There was a small positive correlation between poorer sleep quality and depressive symptoms which showed a trend towards statistical significance (r = 0.21, p = 0.06). In a multivariable regression, poor sleep quality was associated with higher depressive symptom burden, adjusting for participant sex and having a seizure in the previous month (p = 0.01).

CONCLUSIONS

Our exploratory study disentangles the multilayered psychosocial burden of disease experienced by PWE in Bhutan, a lower-middle-income country with access to antiseizure medications and psychiatrists but not expert epilepsy services or human resources. Further investigation into the interrelationships among social isolation, poor sleep quality, depression, and seizure burden could identify preventable and remediable constituents of this burden.

Factors Affecting Cognition and Depression in Adult Patients with Epilepsy

Background and Purpose

Epilepsy patients are more likely to experience depressive symptoms and cognitive impairment compared to individuals in the general population. As the reasons for this are not definitively known, we sought to determine what factors correlate most strongly with cognition and a screening test for depression in epilepsy patients.

Methods

Our study population included 379 adult patients diagnosed with epilepsy or seizure in our neurology clinic. We collected detailed demographic and clinical data during patient visits using structured clinical documentation support tools that we have built within our commercial electronic medical records system (Epic), including a depression score (Neurological Disorders Depression Inventory for Epilepsy, NDDIE) and cognition score test measures (specifically in this study, Mini-Mental State Examination [MMSE]). Medication, age, gender, body mass index, duration of epilepsy, seizure frequency, current number of anti-epileptic medications, years of education were assessed in relation to baseline score as well as change in score from initial visit to first annual follow-up.

Results

Of the analyzed factors, two statistically significant associations were found after correction for multiple testing. Male gender and lower anti-seizure medication count were associated with better mood, as assessed by NDDIE score, at initial visit. Specifically, male gender was associated with a 1.3 decrease in NDDIE and for each additional anti-seizure medication, there was an associated 1.2 increase in NDDIE.

Conclusions

However, these factors were not associated with change in NDDIE score from initial to first annual follow-up visit. These findings, although interesting, are preliminary. Additionally, these findings were based on a homogenous (mainly Caucasian) clinic-based population and detailed information on previous medication use was lacking. Further work is needed to replicate these findings and to understand any mechanisms that may explain these associations.