Utjecaj prinosa mlijeka na funkcionalnu aktivnost neutrofila u krava križanki Karan Fries (Holstein Friesian X Tharparkar) tijekom peripartusnog razdoblja.

To study the immunological activities of neutrophils, blood samples were collected from 6 high yielding (HY) and 6 low yielding (LY) Karan Fries (KF) cows on -15,-7, -5, -3, -2, -1 days prepartum, at calving and on 1, 2, 3, 5, 7 and 15 days postpartum. Plasma cortisol levels, phagocytic activity (PA), enzyme (Elastase, Collagenase and Cathepsin G) levels and expression of TLR-2, TLR-4 and IL-8 were also studied. Both HY KF and LY KF cows were found to have increased blood Total leukocyte counts (TLC) and neutrophil percent at calving, but HY KF cows had significantly (P<0.05) higher levels than LY KF cows. The number of band neutrophils were also significantly (P<0.05) higher in HY cows. Significant (P<0.05) immunosuppression in relation to PA was found for HY as compared to LY KF cows throughout the peripartum period, with the lowest immunosuppression at calving in both groups of cows. Cortisol levels were significantly (P<0.01) higher during calving and negatively correlated with neutrophilic functions. The difference between the two groups also remained significant (P<0.05) as higher level of cortisol were found in HY KF cows. Elastase, collagenase and cathepsin were significantly (P<0.05) decreased during parturition. Elastase was reduced approximately 2.5 times on the day of calving in LY KF cows, but no such major reduction was observed for HY KF cows. Collagenase and cathepsin levels were significantly (P<0.05) higher in LY cows. Expression of the TLR-2 gene was significantly (P<0.05) lower in HY cows during the whole peripartum period than in LY cows. Expression of the TLR-4 gene was significantly (P<0.05) lower on days 15 pre- and post-calving in HY cows. IL-8 differed significantly (P<0.05) only during the prepartum days. Lower neutrophilic function in cross bred cows with high production potential, provides lower disease resistance and makes the cows more susceptible to peripartum infection.S ciljem istraživanja imunološke aktivnosti neutrofila, od šest visokoproizvodnih (VP) i šest niskoproizvodnih (NP) Karan Fries (KF) krava prikupljeni su uzorci krvi -15, -7, -5, -3, -2, -1 dana prije partusa, zatim tijekom partusa, te 1, 2, 3, 5, 7 i 15 dana nakon partusa. Analizirana je razina kortizola u plazmi, aktivnost fagocita (AF), razine enzima (elastaze, kolagenaze, katepsina G) te ekspresija TLR-2, TLR-4 i IL-8. Kod obje skupine krava, VP KF i NP KF, utvrđeno je povećanje ukupnog broja leukocita (UBL) i postotka neutrofila pri teljenju, ali razine su kod VP KF krava bile signifikantno više (P<0,05) nego kod NP KF krava. Broj nesegmentiranih neutrofila bio je također signifikantno (P<0,05) viši kod VP krava. Signifikantna (P<0,05) imunosupresija u odnosu na AF utvrđena je kod VP u usporedbi sa NP KF kravama tijekom peripartusnog razdoblja, s najnižom razinom imunosupresije pri teljenju obje skupine krava. Razine kortizola bile su signifikantno (P<0,01) više tijekom teljenja i negativno povezane s funkcijom neutrofila. Razlike između skupina također su ostale signifikantne (P<0,05) i u slučaju više razine kortizola utvrđene kod VP KF krava. Elastaza, kolagenaza i katepsin signifikantno su (P<0,05) opadali tijekom teljenja. Elastaza je smanjena za približno 2,5 puta na dan teljenja NP KF krava dok kod VP KF krava takvo jako smanjenje nije opaženo. Razine kolagenaze i katepsina bile su signifikantno (P<0,05) više kod NP krava. U odnosu na NP krave, ekspresije TLR-2 gena kod VP krava bile su signifikantno (P<0,05) niže tijekom cijelog peripartusnog razdoblja. Ekspresija TLR-4 gena bila je signifikantno (P<0,05) niža 15. dan prije i poslije teljenja VP krava. IL-8 je bio signifikantno različit (P<0,05) samo tijekom prepartusnog razdoblja. Snižena funkcija neutrofila kod krava križanki s visokim proizvodnim potencijalom doprinosi njihovoj manjoj otpornosti na bolesti i čini ihosjetljivijima na infekcije tijekom peripartusnog razdoblja

A Comparative Study on Changes in Total and Differential Milk Cell Counts, Activity, and Expression of Milk Phagocytes of Healthy and Mastitic Indigenous Sahiwal Cows

Milk somatic cell counts (SCCs) have been used as a gold standard to monitor mammary health as well as an indicator of raw milk quality. The present work was undertaken to compare the changes in the milk SCC, milk differential leukocyte counts (DLCs), phagocytic activity (PA) of milk neutrophils and macrophages (by nitroblue tetrazolium assay), extracellular trap formation (PicoGreen assay) and mRNA expression of various genes in milk neutrophils and macrophages (reverse transcription–polymerase chain reaction), and milk plasma cortisol concentration (enzyme-linked immunosorbent assay) in healthy, subclinical mastitis (SCM), and clinical mastitis (CM) cows. Milk was collected from healthy, SCM, and CM cows grouped based on their SCCs and California mastitis test with eight cows in each group. Milk SCC was estimated by SCC counter, and DLC was done after staining the milk slide under a microscope at 100×. Total SCCs in healthy, SCM, and CM cows were on an average of 128.30, 300.3, and 694.40 × 103 cells/mL, respectively. Milk DLCs indicated a lower percentage of macrophage and lymphocytes and a higher (p &lt; 0.05) percentage of neutrophils in SCM and CM compared to healthy milk. The percentage of mature segmented neutrophils was lower, whereas immature band neutrophils were higher (p &lt; 0.05) in the SCM and CM groups as compared to healthy cows. The viability, in vitro PA, and extracellular trap formation of neutrophils were lower (p &lt; 0.05) in SCM and CM milk samples as compared to healthy samples. However, the PA of macrophage remained unchanged in all the studied groups. The relative mRNA expression of Toll-like receptors (TLR2, TLR4), myeloperoxidase, and interleukin 2α (IL-2α) receptor (CD25) were minimum in healthy samples and increased (p &lt; 0.05) with the progress of mammary inflammation. However, CD44 decreased (p &lt; 0.05), and CD62L remained unchanged in mastitis as compared to healthy cows. Plasma cortisol concentrations were higher (p &lt; 0.05) in mastitis as compared to healthy cows and were negatively correlated with the number of milk macrophages and the functions of milk phagocytes. Estimation of total SCC, milk DLC, and activity of milk phagocytes is essential for effective control and prevention of incidence of mastitis in dairy cows

Neutrophil dynamics in the blood and milk of crossbred cows naturally infected with Staphylococcus aureus

Aim: The present study was designed to evaluate the neutrophil dynamics in terms of the functional competence during subclinical mastitis (SCM) and clinical mastitis (CM). Materials and Methods: A total of 146 Karan fries cows were screened and were divided into three groups as control (n=12), SCM, n=12 and CM, n=12 groups on the basis of California mastitis test scoring, bacteriological evaluation, gross and morphological changes in milk and by counting milk somatic cell count (SCC). Both blood and milk polymorphonuclear neutrophils (PMNs) were isolated in the study. Phagocytic activity (PA) was studied by spectrophotometrically; neutrophil extracelluar traps (NETs) were studied by scanning electron microscopy (SEM); CD44 was quantified by flow cytometry and apoptosis was studied by fluorescent microscopy. Results: Significantly (p<0.05) higher SCC, PA was found in milk of CM cows as compared to SCM and control cows. Significantly lower (p<0.05) apoptosis was observed in PMNs isolated from both blood and milk of CM group of cows when compared to control and SCM group. The milk neutrophils of CM group of cows formed NETs as evidenced from the SEM images. Surface expression of CD44 revealed a significantly (p<0.05) lower expression in milk neutrophils of CM group of cows when compared to SCM and control group of cows. Conclusion: The study indicated a positive correlation between delayed neutrophil apoptosis, persistent staying of neutrophils at the site of infection along with formation of NETs as the strategies to fight against the pathogens in the udder during Staphylococcal mastitis. The study forms a strong base for future molecular research in terms of neutrophil recruitment and neutrophil removal from the site of infection

Surface expression of CD11b, CD62L, CD44 receptors on blood and milk neutrophils during subclinical and clinical mastitis in Sahiwal cows

Surface expression of cell adhering molecules and CD44 was studied in Sahiwal (SW) cows suffering naturally from subclinical (SCM) and clinical mastitis (CM). Cows were divided into groups, viz. healthy (12), SCM (12) and CM (12) groups on the basis of CMT scoring, bacteriological culture, gross morphological changes in the milk and by counting milk SCC after screening of 136 SW cows. Bacteriological culture indicated infection of Staphylococcus aureus as the causative agent of SCM and CM. Healthy cows showed significantly higher CD62L expression as compared to the SCM and CM group of animals in both blood and milk neutrophils but no significant difference was found between blood and milk neutrophils. The results revealed a significant upregulation of CD11b positive cells in the CM group of cows. Significantly higher expression of CD44 was found in the neutrophils of both blood and milk of SCM group as compared to CM group. From the study, it was evident that neutrophils exhibit dynamic interplay between the integrins (CD11b) and selectins (CD62L) along with CD44 during SCM and CM Staphylococcal mastitis to offer host protection against the foreign invaders

Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk outcome pairs, and new data on risk exposure levels and risk outcome associations. Methods: We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017. Findings: In 2017,34.1 million (95% uncertainty interval [UI] 33.3-35.0) deaths and 121 billion (144-1.28) DALYs were attributable to GBD risk factors. Globally, 61.0% (59.6-62.4) of deaths and 48.3% (46.3-50.2) of DALYs were attributed to the GBD 2017 risk factors. When ranked by risk-attributable DALYs, high systolic blood pressure (SBP) was the leading risk factor, accounting for 10.4 million (9.39-11.5) deaths and 218 million (198-237) DALYs, followed by smoking (7.10 million [6.83-7.37] deaths and 182 million [173-193] DALYs), high fasting plasma glucose (6.53 million [5.23-8.23] deaths and 171 million [144-201] DALYs), high body-mass index (BMI; 4.72 million [2.99-6.70] deaths and 148 million [98.6-202] DALYs), and short gestation for birthweight (1.43 million [1.36-1.51] deaths and 139 million [131-147] DALYs). In total, risk-attributable DALYs declined by 4.9% (3.3-6.5) between 2007 and 2017. In the absence of demographic changes (ie, population growth and ageing), changes in risk exposure and risk-deleted DALYs would have led to a 23.5% decline in DALYs during that period. Conversely, in the absence of changes in risk exposure and risk-deleted DALYs, demographic changes would have led to an 18.6% increase in DALYs during that period. The ratios of observed risk exposure levels to exposure levels expected based on SDI (O/E ratios) increased globally for unsafe drinking water and household air pollution between 1990 and 2017. This result suggests that development is occurring more rapidly than are changes in the underlying risk structure in a population. Conversely, nearly universal declines in O/E ratios for smoking and alcohol use indicate that, for a given SDI, exposure to these risks is declining. In 2017, the leading Level 4 risk factor for age-standardised DALY rates was high SBP in four super-regions: central Europe, eastern Europe, and central Asia; north Africa and Middle East; south Asia; and southeast Asia, east Asia, and Oceania. The leading risk factor in the high-income super-region was smoking, in Latin America and Caribbean was high BMI, and in sub-Saharan Africa was unsafe sex. O/E ratios for unsafe sex in sub-Saharan Africa were notably high, and those for alcohol use in north Africa and the Middle East were notably low. Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning

Dodatak kroma u teladi azijskog vodenog bivola (Bubalus bubalis) pod stresom od hladnoće: učinci na prirast, hranidbenu iskoristivost te staničnu i humoralnu imunost

Various stressors significantly increase urinary excretion of chromium (Cr), suggesting that Cr may be physiologically linked to the responses to control stress. The aim of this study was to determine the physiological responses of buffalo calves to increased Cr supply under low ambient temperature. In a randomized complete block design, twenty-four Murrah buffalo calves were assigned to 4 treatments for a period of 120 days. Treatments included either no supplemental Cr (control), 0.5 mg of supplemental Cr/kg DM, 1.0 mg of supplemental Cr/kg DM, or 1.5 mg of supplemental Cr/kg DM. Buffalo calves were monitored daily for physiological variables, dry matter intake (DMI) and fortnightly for body mass change. Blood samples were collected at fortnightly intervals and analyzed for the biomarkers of immunity and plasma trace mineral concentration. At the end of the 120 day experimental period, a 7 day metabolic trial was conducted. The average temperature-humidity index (THI) and relative humidity (RH) during the study were 58.10 units and 52.0% respectively. Physiological variables, DMI and growth performance did not differ among all treatments. 1.5 mg Cr/kg DM increased B and T-cell proliferation, neutrophil phagocytic activity and ferric reducing antioxidant power (FRAP) value, whereas plasma total immunoglobulin (TIg) and immunoglobulin G (IgG) concentrations were the highest in the 1.0 and 1.5 mg Cr/kg DM group. Nutrient digestibility, nitrogen (N) metabolism and trace mineral bioavailability did not differ between treatments, while the bioavailability of Cr showed a positive correlation with supplemental Cr level. The results suggest that in cold conditions, increased Cr supply can improve immune response without affecting physiological response, growth performance and nutrient utilization in buffalo calves.Različiti stresori značajno povećavaju izlučivanje kroma (Cr) mokraćom što naznačuje da Cr može biti fiziološki vezan s odgovorom za kontrolu stresa. Cilj je ovog rada bio odrediti fiziološke odgovore u bivolje teladi na povećani dodatak Cr u uvjetima niske temperature okoliša. Prema metodi slučajnog odabira skupina, 24 Murrah bivolska teleta bila su raspodijeljena u četiri skupine koje su bile različito tretirane u razdoblju od 120 dana. Životinjama jedne skupine dodavano je 0,5 mg Cr/kg suhe tvari, druge skupine 1,0 mg Cr/kg suhe tvari, a treće skupine 1,5 mg Cr/kg suhe tvari, dok kontrolnoj skupini Cr nije bio dodavan. U teladi su dnevno bile promatrane fiziološke varijable, uzimanje suhe tvari te svaka dva tjedna promjena tjelesne mase. Uzorci krvi bili su uzimani u razmacima od 14 dana i pretraženi na biomarkere imunosti i koncentraciju minerala u tragovima u plazmi. Na kraju pokusnog razdoblja od 120 dana proveden je sedmodnevni metabolički pokus. Prosječni indeks temperature i vlažnosti tijekom istraživanja iznosio je 58,10 jedinica dok je relativna vlažnost bila 52,0 %. Fiziološke varijable, uzimanje suhe tvari i prirast reducirajućeg željeza nisu se razlikovali među skupinama. Količina od 1,5 mg Cr/kg suhe tvari povećala je proliferaciju B- i T-limfocita, fagocitoznu aktivnost neutrofila i vrijednost antioksidacijske sposobnosti, dok su koncentracije ukupnih imunoglobulina plazme i imunoglobulina G (IgG) bile najveće u skupinama koje su dobivale 1,0 odnosno 1,5 mg Cr/kg suhe tvari. Nutritivna probavljivost, metabolizam dušika (N) i biološka raspoloživost minerala u tragovima nisu se razlikovali među skupinama. Biološka raspoloživost Cr bila je u korelaciji s razinom njegova dodatka. Rezultati upućuju na zaključak da povećani dodatak Cr u hladnoći može poboljšati imunosni odgovor bez utjecaja na fiziološki odgovor, prirast i hranidbenu iskoristivost u bivolje teladi

Parenteral micronutrient supplementation enhances mammary immune function and colostrum–milk quality by modulating cytokine profiles and oxidative stress in transition crossbred cows

BackgroundThe transition period in dairy cattle is marked by oxidative stress and immune suppression linked to altered micromineral status. This study evaluated whether parenteral supplementation with trace elements and vitamins could enhance mammary health and improve the immunonutritional quality of colostrum and milk.MethodsTwenty-four multiparous cross-bred cows were blocked by parity and projected yield, then assigned to control, multivitamin (MV; vitamins A, B-complex, D₃, E), multi-mineral (MM; Copper (Cu), Manganese (Mn), Selenium (Se), and Zinc (Zn)), or combined multivitamin and multi-mineral (MMMV) groups. Intramuscular injections were administered on days −30, −15, −7, 0, +7, +15, and +30 relative to calving. Longitudinal sampling was conducted on days 0, 2, 3, 4, 7, 15, and 30 postpartum.ResultsMMMV cows produced colostrum and milk with higher fat and protein percentages, stable lactose, and greater concentrations of insulin-like growth factors and immunoglobulins than all other groups (P &lt; 0.05). Mammary health indicators improved concomitantly: somatic cell counts fell, the neutrophil-to-macrophage ratio normalised, and phagocytic activity of both cell types increased. These functional improvements were accompanied by reduced expression of toll-like and chemokine receptors in milk phagocytes. Additionally, the cytokine profile shifted toward an anti-inflammatory state evidenced by lower levels of IL-1β, IL-6, IL-8, IL-17A, and IFN-γ, and higher levels of IL-4 and IL-10. Reduced oxidative stress was indicated by decreased activities of superoxide dismutase, catalase, and glutathione peroxidase in the milk whey of the MMMV group. The MM and MV treatments conferred intermediate benefits, whereas the control group showed the greatest inflammatory and oxidative stress.ConclusionsRepeated parenteral delivery of complementary trace minerals and vitamins throughout the transition period enhances mammary innate immunity, attenuates inflammation and oxidative stress, and augments the nutritive and immunological value of colostrum and milk. This approach offers a practical intervention to safeguard udder health and optimise passive immune transfer to calves

Disruption of Neural Periodicity Predicts Clinical Response After Deep Brain Stimulation for Obsessive-Compulsive Disorder

Recent advances in surgical neuromodulation have enabled chronic and continuous intracranial monitoring during everyday life. We used this opportunity to identify neural predictors of clinical state in 12 individuals with treatment-resistant obsessive-compulsive disorder (OCD) receiving deep brain stimulation (DBS) therapy ( NCT05915741 ). We developed our neurobehavioral models based on continuous neural recordings in the region of the ventral striatum in an initial cohort of five patients and tested and validated them in a held-out cohort of seven additional patients. Before DBS activation, in the most symptomatic state, theta/alpha (9 Hz) power evidenced a prominent circadian pattern and a high degree of predictability. In patients with persistent symptoms (non-responders), predictability of the neural data remained consistently high. On the other hand, in patients who improved symptomatically (responders), predictability of the neural data was significantly diminished. This neural feature accurately classified clinical status even in patients with limited duration recordings, indicating generalizability that could facilitate therapeutic decision-making

Global, regional, and national prevalence and mortality burden of sickle cell disease, 2000–2021: a systematic analysis from the Global Burden of Disease Study 2021

Background Previous global analyses, with known underdiagnosis and single cause per death attribution systems, provide only a small insight into the suspected high population health effect of sickle cell disease. Completed as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, this study delivers a comprehensive global assessment of prevalence of sickle cell disease and mortality burden by age and sex for 204 countries and territories from 2000 to 2021. Methods We estimated cause-specific sickle cell disease mortality using standardised GBD approaches, in which each death is assigned to a single underlying cause, to estimate mortality rates from the International Classification of Diseases (ICD)-coded vital registration, surveillance, and verbal autopsy data. In parallel, our goal was to estimate a more accurate account of sickle cell disease health burden using four types of epidemiological data on sickle cell disease: birth incidence, age-specific prevalence, with-condition mortality (total deaths), and excess mortality (excess deaths). Systematic reviews, supplemented with ICD-coded hospital discharge and insurance claims data, informed this modelling approach. We employed DisMod-MR 2.1 to triangulate between these measures—borrowing strength from predictive covariates and across age, time, and geography—and generated internally consistent estimates of incidence, prevalence, and mortality for three distinct genotypes of sickle cell disease: homozygous sickle cell disease and severe sickle cell β-thalassaemia, sickle-haemoglobin C disease, and mild sickle cell β-thalassaemia. Summing the three models yielded final estimates of incidence at birth, prevalence by age and sex, and total sickle cell disease mortality, the latter of which was compared directly against cause-specific mortality estimates to evaluate differences in mortality burden assessment and implications for the Sustainable Development Goals (SDGs). Findings Between 2000 and 2021, national incidence rates of sickle cell disease were relatively stable, but total births of babies with sickle cell disease increased globally by 13·7% (95% uncertainty interval 11·1–16·5), to 515 000 (425 000–614 000), primarily due to population growth in the Caribbean and western and central sub-Saharan Africa. The number of people living with sickle cell disease globally increased by 41·4% (38·3–44·9), from 5·46 million (4·62–6·45) in 2000 to 7·74 million (6·51–9·2) in 2021. We estimated 34 400 (25 000–45 200) cause-specific all-age deaths globally in 2021, but total sickle cell disease mortality burden was nearly 11-times higher at 376 000 (303 000–467 000). In children younger than 5 years, there were 81 100 (58 800–108 000) deaths, ranking total sickle cell disease mortality as 12th (compared to 40th for cause-specific sickle cell disease mortality) across all causes estimated by the GBD in 2021. Interpretation Our findings show a strikingly high contribution of sickle cell disease to all-cause mortality that is not apparent when each death is assigned to only a single cause. Sickle cell disease mortality burden is highest in children, especially in countries with the greatest under-5 mortality rates. Without comprehensive strategies to address morbidity and mortality associated with sickle cell disease, attainment of SDG 3.1, 3.2, and 3.4 is uncertain. Widespread data gaps and correspondingly high uncertainty in the estimates highlight the urgent need for routine and sustained surveillance efforts, further research to assess the contribution of conditions associated with sickle cell disease, and widespread deployment of evidence-based prevention and treatment for those with sickle cell disease.publishedVersio

Global estimates on the number of people blind or visually impaired by Uncorrected Refractive Error: a meta-analysis from 2000 to 2020

Background: Uncorrected refractive error (URE) is a readily treatable cause of visual impairment (VI). This study provides updated estimates of global and regional vision loss due to URE, presenting temporal change for VISION 2020 Methods: Data from population-based eye disease surveys from 1980–2018 were collected. Hierarchical models estimated prevalence (95% uncertainty intervals [UI]) of blindness (presenting visual acuity (VA) < 3/60) and moderate-to-severe vision impairment (MSVI; 3/60 ≤ presenting VA < 6/18) caused by URE, stratified by age, sex, region, and year. Near VI prevalence from uncorrected presbyopia was defined as presenting near VA < N6/N8 at 40 cm when best-corrected distance (VA ≥ 6/12). Results: In 2020, 3.7 million people (95%UI 3.10–4.29) were blind and 157 million (140–176) had MSVI due to URE, a 21.8% increase in blindness and 72.0% increase in MSVI since 2000. Age-standardised prevalence of URE blindness and MSVI decreased by 30.5% (30.7–30.3) and 2.4% (2.6–2.2) respectively during this time. In 2020, South Asia GBD super-region had the highest 50+ years age-standardised URE blindness (0.33% (0.26–0.40%)) and MSVI (10.3% (8.82–12.10%)) rates. The age-standardized ratio of women to men for URE blindness was 1.05:1.00 in 2020 and 1.03:1.00 in 2000. An estimated 419 million (295–562) people 50+ had near VI from uncorrected presbyopia, a +75.3% (74.6–76.0) increase from 2000 Conclusions: The number of cases of VI from URE substantively grew, even as age-standardised prevalence fell, since 2000, with a continued disproportionate burden by region and sex. Global population ageing will increase this burden, highlighting urgent need for novel approaches to refractive service delivery.publishedVersio