ObjectivePterygium is considered to be a proliferative overgrowth of bulbar conjunctiva that can induce significant astigmatism and cause visual impairment; this is the first meta-analysis to investigate the pooled prevalence and risk factors for pterygium in the global world.DesignA systematic review and meta-analysis of population-based studies.SettingInternational.ParticipantsA total of 20 studies with 900 545 samples were included.Primary outcome measureThe pooled prevalence and risk factors for pterygium.Results20 studies were included. The pooled prevalence of pterygium was 10.2% (95% CI 6.3% to 16.1%). The pooled prevalence among men was higher than that among women (14.5% vs 13.6%). The proportion of participants with unilateral cases of pterygium was higher than that of participants with bilateral cases of pterygium. We found a trend that the higher pooled prevalence of pterygium was associated with increasing geographical latitude and age in the world. The pooled OR was 2.32 (95% CI 1.66 to 3.23) for the male gender and 1.76 (95% CI 1.55 to 2.00) for outdoor activity, respectively.ConclusionsThe pooled prevalence of pterygium was relatively high, especially for low latitude regions and the elderly. There were many modifiable risk factors associated with pterygium to which healthcare providers should pay more attention.

BackgroundAlthough diabetic retinopathy (DR) is considered to be a major cause of blindness, this is the first meta-analysis to investigate the pooled prevalence of DR in mainland China.Methodology/Principal FindingsWe conducted a search of all English reports on population-based studies for the prevalence of DR using Medline, EMbase, Web of Science, Google (scholar), and all Chinese reports were identified manually and on-line using CBMDisc, Chongqing VIP database, and CNKI database. A meta-analysis was carried out. The fixed effects model or random effects model was used as a statistical test for homogeneity. Nineteen studies were included. The prevalence of DR, non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) in the pooled general population was 1.3% (95%CI: 0.5%–3.2%), 1.1% (95%CI: 0.6%–2.1%), and 0.1% (95%CI: 0.1%–0.3%), respectively, but was 23% (95%CI: 17.8%–29.2%), 19.1% (95%CI: 13.6%–26.3%), and 2.8% (95%CI: 1.9%–4.2%) in the diabetic group. The prevalence rate of DR in the pooled rural population was higher than that in the urban population, 1.6% (95%CI: 1.3%–2%), and the diabetic population, 29.1% (95%CI: 20.9%–38.9%). The prevalence of DR was higher in the Northern region compared with the Southern region.Conclusions/SignificanceThe prevalence of DR in mainland China appeared a little high, and varied according to area. NPDR was more common. This study highlights the necessity for DR screening in the rural areas of China.

Herein we review and discuss epidemiological, clinical, and experimental studies on diabetic cystopathy, a common chronic complication of diabetes mellitus with a variety of lower urinary tract symptoms, providing directions for future research. A search of published epidemiological, clinical, or preclinical trial literature was performed using the key words "diabetes", "diabetic cystopathy", "diabetic bladder dysfunction", "diabetic lower urinary tract dysfunction", "diabetic detrusor instability". The classic symptoms of diabetic cystopathy are decreased bladder sensation, increased bladder capacity, and impaired bladder emptying with resultant increased post-void residual volume. However, recent clinical evidence indicates a presence of storage symptoms, such as overactive bladder symptoms. The pathophysiology of diabetic cystopathy is multifactorial, including disturbances of the detrusor, neuron, urothelium, and urethra. Hyperglycemia, oxidative stress, and polyuria play important roles in inducing voiding dysfunction in diabetic individuals. Treatment choice depends on clinical symptoms and urodynamic abnormalities. Urodynamic evaluation is the cornerstone of diagnosis and determines management strategies. Diabetes mellitus could cause a variety of lower urinary tract symptoms, leading to diabetic cystopathy with broadly varied estimates of the prevalence rates. The exact prevalence and pathogenesis of diabetic cystopathy remains to be further investigated and studied in multicenter, large-scaled, or randomized basic and clinical trials, and a validated and standardized workup needs to be made, improving diabetic cystopathy management in clinical practice. Further studies involving only female diabetics are recommended.