Patients with radiographic axial spondylarthritis have an impaired dietary intake-a cross-sectional study with matched controls from northern Sweden.

BACKGROUND: Radiographic axial spondyloarthritis (r-axSpA) is one of the most common chronic inflammatory rheumatic diseases, affecting about 0.2% of the Swedish population. Adequate nutritional intake is essential for maintaining physiological functions. A poor diet increases the risk of developing conditions such as obesity, osteoporosis, and/or atherosclerosis. Diet quality is also theorized to affect systemic inflammation. Dietary habits in patients with r-axSpA are largely unknown. The aims of this study were to assess dietary nutrient intake in r-axSpA patients and examine whether it differs compared to persons without r-axSpA. METHODS: r-axSpA patients (modified NY criteria) at the rheumatology clinic in Region Västerbotten, northern Sweden, were invited to take part in the Backbone study which investigates disease severity and comorbidities. In total, 155 patients were included. Nutritional intake was assessed by the semi-quantitative food frequency questionnaire MiniMeal-Q. Controls were collected from the Swedish CArdioPulmonary bioImage Study (n = 30,154), a study that invited participants 50-64 years of age by random selection from the Swedish population register. Out of the 155 r-axSpA patients, 81 were in the same age span. Four controls were identified for each patient, matched on age (± 1 year), sex, and geographic location. Data on dietary intake was available for 319 controls. Statistical comparisons of dietary intake between patients with r-axSpA and controls were done by exact conditional logistic regression analysis, adjusted for country of birth, educational level, single household, weight, smoking status, and energy intake. RESULTS: Patients had a comparatively significantly higher energy intake from carbohydrates, a lower fiber density, and a lower intake of marine omega-3 fatty acids. Furthermore, intake of vitamins D, E, and K as well as selenium, folate, calcium, magnesium, phosphorus, potassium, vitamin A, and ß-carotene (a precursor of vitamin A and marker of vegetable and fruit intake) was significantly lower among patients compared to controls. CONCLUSIONS: Our results suggest that r-axSpA patients have an impaired dietary intake. Notably, intake was lower in several nutrients theorized to have anti-inflammatory properties (fiber density, marine-omega-3 fatty acids, vitamin D, and selenium). We further propose that nutrition screening might be incorporated into the management of r-axSpA patients.

Increased corneal hysteresis after corneal collagen crosslinking: a study based on applanation resonance technology.

IMPORTANCE: A reliable tool for quantification of the biomechanical status of the cornea in conjunction with corneal collagen crosslinking (CXL) treatment is needed. OBJECTIVE: To quantify the biomechanical effects of CXL in vivo. DESIGN, SETTING, AND PARTICIPANTS: A prospective, open, case-control study was conducted at the Department of Ophthalmology, Umeå University, Umeå, Sweden. Participants included 28 patients (29 eyes) aged 18 to 28 years with progressive keratoconus and corresponding age- and sex-matched healthy individuals serving as controls. All participants were monitored during a 6-month period between October 13, 2009, and November 5, 2012. MAIN OUTCOMES AND MEASURES: Corneal hysteresis after CXL for keratoconus. RESULTS: A difference in corneal hysteresis between the control group and the patients with keratoconus was found at baseline, both with an applanation resonance tonometer (ART) and an ocular response analyzer (ORA), at mean (SD) values of -1.09 (1.92) mm Hg (99% CI, -2.26 to 0.07; P = .01) and -2.67 (2.55) mm Hg (99% CI, -4.05 to -1.32; P < .001), respectively. Increased corneal hysteresis was demonstrated with an ART 1 and 6 months after CXL, at 1.2 (2.4) mm Hg (99% CI,-0.1 to 2.5; P = .02) and 1.1 (2.7) mm Hg (99% CI, -0.3 to 2.6; P = .04), respectively, but not with ORA. A decrease in corneal thickness was seen 1 and 6 months after treatment (-24 [26] µm, P < .001; and -11 [21] µm, P = .01, respectively), and a corneal flattening of -0.6 (0.7) diopters was seen at 6 months (P < .001). No significant change in intraocular pressure was identified in patients with keratoconus with any method, except for an increase at 1 month with Goldmann applanation tonometry (P = .005). CONCLUSIONS AND RELEVANCE: To our knowledge ART is the first in vivo method able to assess the increased corneal hysteresis after CXL treatment. Given the large-scale use of CXL in modern keratoconus treatment, a tool with this capacity has a great potential value. Refinement of the ART method of measuring and quantifying corneal biomechanical properties will be a subject of further studies.

Initial results from mechanical compression of the cornea during crosslinking for keratoconus.

PURPOSE: To compare refractive changes after corneal crosslinking with and without mechanical compression of the cornea. METHODS: In a prospective, open, randomized case-control study conducted at the Department of Ophthalmology, Umeå University Hospital, Sweden, sixty eyes of 43 patients with progressive keratoconus aged 18-28 years planned for corneal crosslinking and corresponding age- and sex-matched control subjects were included. The patients were randomized to conventional corneal crosslinking (CXL; n = 30) or corneal crosslinking with mechanical compression using a flat rigid contact lens sutured to the cornea during treatment (CRXL; n = 30). Subjective refraction and ETDRS best spectacle-corrected visual acuity (BSCVA), axial length measurement, keratometry and pachymetry were performed before and 1 and 6 months after treatment. RESULTS: The keratoconus patients had poorer BSCVA, higher refractive astigmatism and higher keratometry readings than the control subjects at baseline (p < 0.01). In the CXL group, BSCVA increased from 0.19 ± 0.26 to 0.14 ± 0.18 logMar (p = 0.03), and the spherical equivalent improved from -1.9 ± 2.8 D to -1.4 ± 2.4 D (p = 0.03). Maximum keratometry readings decreased after CXL from 53.1 ± 4.9 D to 52.6 ± 5.2 D (p = 0.02), and the axial length decreased in the CXL group, likely due to post-treatment corneal thinning (p = 0.03). In the CRXL group, all the above variables were unaltered (p > 0.05). CONCLUSION: At 6 months, the refractive results from CRXL did not surpass those of conventional CXL treatment. Rather, some variables indicated a slightly inferior effect. Possibly, stronger crosslinking would be necessary to stabilize the cornea in the flattened configuration achieved by the rigid contact lens.

Spatial distribution of corneal light scattering after corneal collagen crosslinking.

PURPOSE: To assess the spatial distribution and time course of increased corneal light scattering after corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A irradiation. SETTING: Umeå University Hospital Eye Clinic, Umeå, Sweden. DESIGN: Case series. METHODS: Eyes with keratoconus were examined with Scheimpflug photography before and 1 and 6 months after CXL. Corneal light scattering was quantified throughout the corneal thickness at 8 measurement points 0.0 to 3.0 mm from the central cornea. RESULTS: The study comprised 11 eyes of 11 patients. Central corneal light scattering increased significantly 1 month after CXL (P<.001). At 6 months, it decreased (P = .002); however, it was still higher than pretreatment values (P<.001). Light scattering at 1 month was more pronounced in the superficial stroma, gradually diminishing to zero at 240 µm depth. It was greater at the corneal center than 1.0 to 3.0 mm from the center. At 6 months, a second peak of light scattering occurred between 240 µm and 340 µm depth. No increased light scattering deeper than 340 µm was seen at either time point. CONCLUSIONS: Corneal light scattering after CXL showed distinctive spatial and temporal profiles. Analysis of corneal light scattering may give an impression of tissue changes, the depth of the CXL treatment effect, and the corneal response to the treatment. Scheimpflug photography appears to be useful for this purpose. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.