resolution on psoriasis (WHA 67.9). All Member States recognized the burden of psoriasis and committed to increase their efforts to fight the stigma and unnecessary exclusion of people living with psoriasis. They recognized as well that too many people in the world suffer needlessly from psoriasis due to incorrect or delayed diagnosis, inadequate treatment options and insufficient access to care. The resolution requested WHO to prepare a global report on psoriasis, drawing attention to the public health impact of psoriasis. The resolution also encouraged Member States to engage in advocacy efforts, to raise awareness regarding the disease of psoriasis and fighting off stigmatization suffered by those with psoriasis. WHO recognizes the urgent need to pursue multilateral efforts to raise awareness regarding the disease of psoriasis and to fight stigmatization suffered by those with psoriasis. This report is written to help raise awareness of the range of ways that psoriasis can impact on people’s lives. It aims at empowering policymakers with practical solutions to improve the health care and the social inclusion of individuals with psoriasis – and other NCDs – in society. Alcohol Global report on psoriasis 7 Chapter 2. The burden of psoriasis Psoriasis occurs worldwide. It affects men and women of all ages, regardless of ethnic origin, in all countries (1). Published data on the prevalence of psoriasis in countries vary between 0.09% (2) and 11.4% (3). In most developed countries, prevalence is between 1.5 and 5% (27). There is also evidence to suggest that the prevalence of psoriasis may be increasing (3). Many studies have demonstrated that psoriasis can impact substantially on QoL, even when a relatively limited body surface area (BSA) is affected (16,17,22,28–32). Incidence and prevalence There are very few studies on the incidence1 of psoriasis. Registration of psoriasis cases is not compulsory, meaning reliable data are difficult to find. A review of published literature revealed only a handful of credible studies on the incidence of psoriasis. One study showed that the overall sex- and age-adjusted incidence rate of psoriasis in Minnesota in the United States, between 1980 and 1983, was estimated at 0.60 per 1000 person-years (33). A study of 511 532 individuals in Italy between 2001 and 2005 reported an incidence of psoriasis (adults receiving a first-ever diagnosis of psoriasis) of 2.30–3.21 cases per 1000 person-years (12). In 2012, a 2-week psoriasis screening study via medical consultation was performed in three countries simultaneously – Algeria, Tunisia and Morocco, where incidence of psoriasis was estimated at 10.36, 13.26 and 15.04 per 1000, respectively (34). Relatively more studies have focused on the prevalence of psoriasis. A review of published literature found 68 full articles and reports estimating prevalence rates for 20 countries (Table 1). It should be noted, however, that the data they contain are extremely difficult to compare with each other, due to the different methodologies of the studies and their limitations. The main problems are differences in the definition of prevalence (point prevalence, cumulative prevalence, period prevalence), case definition of psoriasis (selfreported, physician diagnosed), the population ages studied (children only, adults only, any age group) and the sampling techniques (questionnaires, clinical examination, combination of clinical examination and questionnaire, registry data). This difference in methodology clearly impacted on the prevalence rates. Depending on the region, the prevalence studies varied from 0.09% in the United Republic of Tanzania (2) to 11.4% in Norway (3). A very weak correlation between geographic latitude and psoriasis prevalence was found (35). Psoriasis appears to occur most commonly in populations of northern Europe (3,36) and least in populations of eastern Asia (37–45) Some studies investigated the ethnic differences in the prevalence of psoriasis. According to a 2001 study in the United States, people with Caucasian or Black ancestry and others had a prevalence of 2.5%, 1.3% and 1.0%, respectively (14). In another United States study from 2009–2010, these differences were higher, with the prevalence for Caucasians, Blacks, Hispanics and