Quantitative sensory testing and chronic pain syndromes: a cross-sectional study from TwinsUK.

OBJECTIVE: The chronic pain syndromes (CPS) include syndromes such as chronic widespread pain (CWP), dry eye disease (DED) and irritable bowel syndrome (IBS). Highly prevalent and lacking pathognomonic biomarkers, the CPS are known to cluster in individuals in part due to their genetic overlap, but patient diagnosis can be difficult. The success of quantitative sensory testing (QST) and inflammatory biomarkers as phenotyping tools in conditions such as painful neuropathies warrant their investigation in CPS. We aimed to examine whether individual QST modalities and candidate inflammatory markers were associated with CWP, DED or IBS in a large, highly phenotyped population sample. DESIGN: Cross-sectional study. SETTING: Community-dwelling cohort. PARTICIPANTS: Twins from the TwinsUK cohort PRIMARY AND SECONDARY OUTCOME MEASURES: We compared 10 QST modalities, measured in participants with and without a CWP diagnosis between 2007 and 2012. We investigated whether inflammatory markers measured by Olink were associated with CWP, including interleukin-6 (IL-6), IL-8, IL-10, monocyte chemoattractant protein-1 and tumour necrosis factor. All analyses were repeated in DED and IBS with correction for multiple testing. RESULTS: In N=3022 twins (95.8% women), no association was identified between individual QST modalities and CPS diagnoses (CWP, DED and IBS). Analyses of candidate inflammatory marker levels and CPS diagnoses in n=1368 twins also failed to meet statistical significance. CONCLUSION: Our findings in a large population cohort suggest a lack of true association between singular QST modalities or candidate inflammatory markers and CPS.

Greater adherence to a mediterranean diet is associated with lower C-reactive protein (CRP) levels, but not to lower odds of having dry eye disease.

PURPOSE: To investigate the hypothesis that a Mediterranean diet is associated with a lower risk of having dry eye disease (DED) in the general population. METHODS: DED was assessed using the Women's Health Study (WHS) dry eye questionnaire in 58,993 participants from the Dutch Lifelines Cohort with complete available dietary data (20-94 years, 60% female). Level of adherence to a traditional Mediterranean diet was assessed using the modified Mediterranean Diet Score (mMDS). High-sensitivity C-reactive Protein (hsCRP) was included as a marker of whole-body inflammation. Logistic regressions were used to examine the relationship between WHS-defined DED and mMDS, corrected for age, sex, BMI, education, income, and 48 potentially confounding comorbidities. The association between mMDS and hsCRP, and hsCRP and DED, was further explored in separate regressions. RESULTS: Of all participants, 9.1% had DED. In contrast to the hypothesis, higher mMDS levels were associated with greater odds of DED, corrected for demographics, smoking status, BMI, and comorbidities (OR 1.034, 95%CI: 1.015 to 1.055, P = 0.001). Moreover, there was a highly significant relationship between increasing mMDS and lower circulating hsCRP levels; however, there was no significant relationship between hsCRP and DED. CONCLUSIONS: Stronger adherence to a Mediterranean diet does not appear to be associated with lower odds of having DED in the general population. Furthermore, there was no association between hsCRP and DED in this study. However, the previously described link between a Mediterranean diet and lower hsCRP was confirmed in this large population-based study.

TFOS Lifestyle: Impact of nutrition on the ocular surface.

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

The relationship between sedentary behavior and dry eye disease.

PURPOSE: Sedentary behavior (SB) has been linked with low-grade systemic inflammation, which could play a role in the development of dry eye disease (DED). This cross-sectional study aims to investigate the association between SB and DED. METHODS: We assessed 48,418 participants from the population-based Lifelines cohort (58% female, 18-96 years). Women's Health Study (WHS)-defined DED was the primary outcome. SB was assessed using the Marshall Sitting Questionnaire. The relationship between DED and SB was analyzed using logistic regressions, corrected for age, sex, BMI, smoking status, demographics, and 48 comorbidities. Any potential modifying effect of physical activity (PA) was also assessed, and the analyses were repeated excluding the most computer-intensive domains, investigating SB independent from screen exposure. RESULTS: WHS-defined DED was present in 9.1% of participants. Greater SB was associated with an increased risk of DED (odds ratio (OR) 1.015 per hour/day, 95%CI 1.005-1.024, P = 0.004). The association between SB and DED was only significant for those with less than WHO-recommended PA (OR 1.022, 95%CI 1.002-1.042, P = 0.027), and not in participants meeting WHO's recommendation (OR 1.011, 95%CI 0.999-1.023, P = 0.076). Lastly, when excluding computer-related sitting, the relationship between SB and DED was attenuated, and no longer significant (OR 1.009, 95%CI 0.996-1.023, P = 0.19). CONCLUSIONS: Greater sedentary time was tied to an increased risk of DED, especially for those with lower PA levels than WHO recommendations. However, as there was no significant association when computer-intensive sitting time was excluded, screen use could explain the observed relationship and should be noted as a possible key confounder.

The work-related burden of dry eye.

PURPOSE: To investigate the relationship between dry eye disease (DED) and work functioning, unemployment, absenteeism, and worry about job loss. METHODS: DED and unemployment, absenteeism, and 'worry about job loss' were assessed in 71,067 subjects (18-65 years, 60% female) from the Dutch population-based Lifelines cohort using the Women's Health study questionnaire and single-item questions, respectively. Work functioning was assessed in 32,475 participants using the Work role functioning questionnaire 2.0. The relationships between DED and work measures were assessed with logistic regression models, corrected for age, sex, BMI, income, educational level, smoking, and 48 comorbidities. RESULTS: 8.3% of participants had DED and had more impaired work functioning compared to those without DED (49.2% vs 41.1%, OR 1.21, 95% CI 1.10-1.32, corrected for demographics, smoking and 48 comorbidities). DED carried a similar risk of impaired work functioning as rheumatoid arthritis. For participants with highly symptomatic dry eye impaired work functioning was even higher (59.1%) and similar to that of depression. The impaired work functioning seen with increasing symptoms were greater in undiagnosed subjects versus diagnosed subjects (P = 0.03). After correction for comorbidities, DED remained tied to absenteeism and increased worry about job loss, but not unemployment. CONCLUSION: DED was linked to impaired work functioning and absence, but not unemployment. DEDs impact on work functioning is comparable to that of other severe chronic disorders, and undiagnosed subjects may be more affected. This highlights the importance of recognizing DED as a severe disorder and of screening for dry eye in the workplace to aid with diagnosis and treatment.

The relationship between habitual water intake and dry eye disease.

PURPOSE: The purpose of this study is to test the hypothesis that greater habitual water intake is associated with lower risk of dry eye disease (DED). METHODS: We included 51 551 participants from the population-based Lifelines cohort (mean age = 51.2 years) in this cross-sectional association study. DED was assessed using the Women's Health Study (WHS) dry eye questionnaire. Water intake was calculated from food frequency questionnaires. Logistic regressions were used to analyse the relationship between DED and water intake or 24-h urine volume, corrected for age, sex, body mass index, physical activity, smoking status, education, income, 48 comorbidities, and 15 medication groups. The main outcome measure was WHS-defined DED. Highly symptomatic dry eye and clinical diagnosis of DED were secondary outcomes. RESULTS: In total, 9.1% of the population had WHS-defined DED. Higher water intake was associated with increased prevalence of WHS-defined DED (OR: 1.011 per 100 ml/day, 95% CI: 1.004-1.017, p = 0.003). After excluding those with a clinical diagnosis, greater water intake was still tied to increased risk of having DED symptoms (OR: 1.010 per 100 ml/day, 95% CI: 1.006-1.015, p < 0.001). Higher 24-h urine volumes were also associated with higher risk of WHS-defined DED (OR: 1.010 per 100 ml/day, 95% CI: 1.005-1.015, p < 0.001). CONCLUSIONS: In this large, population-based study, higher water intake was not tied to reduced risk of DED. Rather, it was associated with a modest increased risk of DED. Interventional studies are needed to fully understand the effect of water intake on DED, but this study found no evidence that greater water intake is beneficial for DED.

The Relationship Between Caffeine Intake and Dry Eye Disease.

PURPOSE: The aim of this study was to determine the association between caffeine intake and dry eye disease (DED) in the large, population-based LifeLines cohort in the Netherlands. METHODS: DED was cross-sectionally assessed in 85,302 participants (59% female participants) using the Women's Health Study dry eye questionnaire. Dietary caffeine was calculated from the intake of coffee, tea, cola, and energy drinks. Logistic regression was used to investigate the relationship between DED and caffeine, correcting for demographic variables, smoking status, alcohol intake, and 48 comorbidities of DED. RESULTS: The mean (SD; range) age of participants was 50.7 years (12.4; 18-96), and 50,339 (59%) were female. The mean (SD) caffeine intake was 285 (182) mg/d. After correcting for demographics, body mass index, smoking status, and alcohol intake, higher caffeine intake was associated with a decreased risk of Women's Health Study-defined DED [odds ratio (OR) 0.971 per 100 mg/d, 95% CI, 0.956-0.986, P < 0.0005]. When additionally adjusting for medical comorbidities, no significant effect was observed (OR 0.985, 95% CI, 0.969-1.001, P = 0.06). Caffeine's effect on DED was similar in male and female participants and independent of sleep quality and stress at work. Decaffeinated coffee intake was significantly associated with an increased risk of DED, when adjusted for caffeinated coffee, demographics, alcohol intake, smoking status, and comorbidities (OR 1.046 per cup/d, 95% CI, 1.010-1.084, P = 0.01). None of the beverages were significantly associated with the risk of DED, when correcting for intake of the other caffeinated beverages, demographics, smoking status, alcohol intake, and all comorbidities. CONCLUSIONS: Dietary caffeine intake does not seem to be a risk factor for DED in the general population.

The vision-related burden of dry eye.

PURPOSE: To investigate the relationship between dry eye disease (DED) and vision-related quality of life (VR-QoL) at population level. METHODS: DED and VR-QoL were assessed in 89,022 participants (18-96 years, 59% female) from the Dutch population-based Lifelines cohort using the Women's Health study (WHS) and Visual function 25 (VFQ25) questionnaires. The relationship between DED and compromised VR-QoL was assessed with logistic regression, corrected for age, sex, BMI, income, education, smoking, and 55 comorbidities. RESULTS: 9.1% of participants had DED. The participants with DED had higher risk of compromised average of ten domains of VR-QoL (OR 3.12 (95% CI 2.98-3.27) corrected for age, sex, BMI, income, smoking, and 55 comorbidities). Increasing symptom frequency was highly associated with decreasing VR-QoL (P < 0.0005). In all VR-QoL domains, including measures of daily visual function and emotional well-being, DED was clearly associated with compromised VR-QoL. Compared to macular degeneration, glaucoma, retinal detachment, and allergic conjunctivitis, DED presented similar or higher risks for compromised score on all VR-QoL domains. The population-attributable fraction of DED for compromised general vision exceeded that of other eye diseases investigated, especially in the younger age groups. CONCLUSION: DED is associated with reductions in all domains of VR-QoL, also after correction for associated comorbidities. We found that DED imposes an extensive population burden regarding compromised VR-QoL due to its high prevalence and substantial impact on VR-QoL, higher than that for other common vision-affecting eye disorders. Our results emphasize the importance of recognizing DED as a serious disorder from both patient and public health perspectives.

The relationship between alcohol consumption and dry eye.

PURPOSE: To assess the association between dry eye disease (DED) and alcohol consumption using a large population-based cohort. METHODS: 77,145 participants (19-94 years, 59% female) from the Dutch Lifelines cohort were cross-sectionally assessed for DED using the Women's Health Study (WHS) dry eye questionnaire. Alcohol intake was assessed using self-reported food frequency questionnaires. The relationship between DED and alcohol use was analyzed using logistic regression, corrected for age, sex, BMI, smoking status, education, income, and 55 potentially confounding comorbidities. RESULTS: Overall, 30.0% of participants had symptomatic dry eye. Alcohol use significantly increased the risk of symptomatic dry eye in females (odds ratio [OR] 1.095, 95%CI 1.045-1.148), but not in males (OR 0.988, 95%CI 0.900-1.084). Contrarily, in male drinkers, increasing alcohol intake (in 10 g/day) had a protective effect on symptomatic dry eye (OR 0.962, 95%CI 0.934-0.992), which was not seen in females (OR 0.986, 95%CI 0.950-1.023). Alcohol use and intake had a sex-specific effect on all outcomes of DED assessed: symptomatic dry eye, highly symptomatic dry eye, clinical diagnosis, and WHS definition dry eye. CONCLUSIONS: This large population-based study found alcohol use to have a clear sex-specific effect on DED, presenting as a risk-factor only in females. This adds to the evidence of sex-specific pathophysiological mechanisms of dry eye and illustrates the importance of sex stratification in studies investigating DED. The mild protective effect of increased alcohol intake in male drinkers is advised to be interpreted with caution, as alcohol's other health effects might be of greater clinical significance.

Association Between Medication-Taking and Refractive Error in a Large General Population-Based Cohort.

Purpose: Refractive errors, particularly myopia, are common and a leading cause of blindness. This study aimed to explore associations between medications and refractive error in an aging adult cohort and to determine whether childhood-onset refractive errors predict future medication use to provide novel insights into disease mechanisms. Methods: The study compared the spherical equivalent values measured in 102,318 UK Biobank participants taking the 960 most commonly used medications. The strengths of associations were evaluated against the self-reported age of spectacle wear. The causality of refractive error changes was inferred using sensitivity and Mendelian randomization analyses. Results: Anti-glaucoma drugs were associated with 1 to 2 diopters greater myopic refraction, particularly in subjects who started wearing correction in the first two decades of life, potentially due to the association of higher intraocular pressure since early years with both myopia and, later in life, glaucoma. All classes of pain-control medications, including paracetamol, opiates, non-steroidal antiinflammatory drugs, and gabapentinoids, were associated with greater hyperopia (+0.68-1.15 diopters), after correction for deprivation, education, and polypharmacy and sensitivity analyses for common diagnoses. Oral hypoglycemics (metformin, gliburonide) were associated with myopia, as was allopurinol, and participants using bronchodilators (ipratropium and salbutamol) were more hyperopic. Conclusions: This study finds for the first time, to our knowledge, that medication use is associated with refractive error in adults. The novel finding that analgesics are associated with hyperopic refraction, and the possibility that multisite chronic pain predisposes to hyperopia, deserves further research. Some drugs, such as antihyperglycemic or bronchodilators, may directly alter refractive error. Intraocular pressure appears causative for myopia.

Clinical Phenotyping of Primary Sjögren Syndrome Patients Using Salivary Gland Ultrasonography: Data From the RESULT Cohort.

OBJECTIVE: To investigate salivary gland ultrasound (SGUS) abnormalities in relation to clinical phenotype and patient characteristics, disease activity, and disease damage in patients with primary Sjögren syndrome (pSS). METHODS: Consecutive outpatients included in our REgistry of Sjögren Syndrome LongiTudinal (RESULT) cohort were selected. Patients with pSS who were included were classified according to the American College of Rheumatology/European League Against Rheumatism (EULAR) criteria and underwent full ultrasonographic examination (Hocevar score 0-48) at baseline. Total SGUS scores of ≥ 15 were considered positive. Patient characteristics, disease activity, and disease damage were compared between the different SGUS groups. RESULTS: In total, 172 of 186 patients with pSS were eligible, of whom 136 (79%) were SGUS positive. Compared with patients who were SGUS negative, SGUS-positive patients had significantly longer disease duration, higher EULAR Sjögren Syndrome Disease Activity Index, higher Sjögren Syndrome Disease Damage Index, and were more likely to have a positive parotid gland biopsy, anti-SSA/SSB antibodies, and abnormal unstimulated whole saliva (UWS) and ocular staining score (OSS), and higher levels of IgG and rheumatoid factor. Regarding patient-reported outcome measurements (PROM), patients who were SGUS positive scored significantly lower on the EULAR Sjögren Syndrome Patient-Reported Index for fatigue and pain, and more often found their disease state acceptable compared with patients who were SGUS negative. SGUS total score showed significant associations with various clinical and serological variables, and with PROM. Highest associations were found for UWS (ρ = -0.551) and OSS (ρ = 0.532). CONCLUSION: Patients who were SGUS positive show a distinct clinical phenotype in all aspects of the disease compared with patients who were SGUS negative: clinical, functional, serological, and PROM. SGUS could be a helpful tool in selecting patients for clinical trials and estimating treatment need.

Prevalence and risk factors of dry eye in 79,866 participants of the population-based Lifelines cohort study in the Netherlands.

PURPOSE: To investigate the prevalence of dry eye among all adult age categories and to discover independent risk factors by investigating a wide range of etiological categories. METHODS: A cross-sectional association study including 79,866 voluntary participants aged 20-94 years of the population-based Lifelines Cohort Study in the Netherlands. RESULTS: Overall, 9.1% of participants had dry eye disease as measured by the Women's Health Study dry eye questionnaire. Prevalence of dry eye symptoms were particularly prevalent in 20-30 years olds. Dry eye was associated with comorbidities in almost all body systems, including musculoskeletal, gastro-intestinal, ophthalmic, autoimmune, psychiatric, pain, functional, dermatological and atopic disorders. Numerous independent risk factors were discovered or confirmed, with strong associations for female sex, contact lens use, irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, eye surgery including cataract and laser refractive surgery, keratoconus, osteoarthritis, connective tissue diseases, atherosclerosis, Graves' disease, autistic disorder, depression, 'burnout', Crohn's disease, sarcoid, lichen planus, rosacea, liver cirrhosis, sleep apnea, sinusitis, thyroid function, and air pollution (NO2). High blood pressure and high BMI were strongly associated with less dry eye, as was current smoking, while ex-smokers had more dry eye. No clear link between dry eye and lipid or blood glucose levels was found. CONCLUSIONS: This study on dry eye confirmed but also refuted many risk factors from smaller epidemiological studies, and discovered numerous new risk factors in multiple etiological categories. The finding that dry eye symptoms are particularly common in young adults is concerning, and warrants further study.

Clinical Characteristics of Dry Eye Patients With Chronic Pain Syndromes.

PURPOSE: To investigate clinical characteristics of dry eye disease (DED) patients with a chronic pain syndrome. DESIGN: Cross-sectional study. METHODS: Four hundred twenty-five patients of a tertiary care DED patient cohort in the Netherlands were included. Chronic pain syndromes irritable bowel syndrome, chronic pelvic pain, and fibromyalgia were assessed by questionnaires. Outcome variables were the Ocular Surface Disease Index (OSDI) symptom questionnaire, tear osmolarity, Schirmer test, tear breakup time, conjunctival hyperemia, staining of the cornea and conjunctiva, and amount of mucus. Outcomes were cross-sectionally compared between DED patients with a chronic pain syndrome and those without. RESULTS: A total of 74 out of 425 DED patients (17%) had at least 1 chronic pain syndrome. The total symptom score was significantly higher in DED patients with a chronic pain syndrome than in those without (45.8 vs 33.8, P < .0005). Moreover, patients with a chronic pain syndrome scored higher on every single subscale of the 12-item OSDI symptom questionnaire. However, ocular signs were similar or even less severe in these patients. Similarly, in 64 DED patients from the population-based cohort TwinsUK, patients with a chronic pain syndrome (n = 24, 38%) had higher subscale and total (34.1 vs 14.4, P = .001) symptom scores. CONCLUSION: In DED patients, chronic pain syndromes are common and are associated with increased severity of DED symptoms across all domains of the OSDI, even though objective ocular surface signs are no worse. In clinical practice, more awareness of chronic pain syndromes might help in understanding the discrepancy between signs and symptoms in DED.

Prevalence and risk factors of dry eye disease in a British female cohort.

BACKGROUND/AIMS: To estimate the prevalence and risk factors of dry eye disease (DED) in a female cohort in the UK. METHODS: Population-based cross-sectional association study of 3824 women from the TwinsUK cohort aged 20-87 years. A questionnaire was used to evaluate DED and several risk factors. Binary logistic regression, corrected for age, was used to examine the association between DED and risk factors. RESULTS: 9.6% of women had a DED diagnosis and concomitant use of artificial tears, and 20.8% experienced DED symptoms in the past 3 months. Risk factors that were significantly associated with DED were age, asthma, eczema, the presence of any allergy, cataract surgery, rheumatoid arthritis, osteoarthritis, migraine and stroke. The highest effect sizes were found with depression, pelvic pain, irritable bowel syndrome and chronic widespread pain syndrome (all p<0.0005). Subjects with DED symptoms scored significantly lower on self-perceived health, compared with controls (p=0.001). CONCLUSIONS: DED is common and increases with age within this cohort of female twins. We confirmed established risk factors for the first time in a British population, and found important risk factors that might relate to an underlying aetiology involving chronic pain predisposition or somatisation.