Gout is the most common inflammatory joint disease in men, characterised by formation of monosodium urate (MSU) crystals in the synovial fluid of joints and in other tissues. The epidemiology of gout provides us with the understanding of the disease distribution and its determinants. In an attempt to update the knowledge on the topic, more recent research reports on the descriptive epidemiology of gout are reviewed in this article. The review describes clinical characteristics and case definitions of gout, including the Rome and New York diagnosis criteria of gout, ‘1977 American Rheumatism Association (ARA) criteria’ and the 10 key propositions of the European League Against Rheumatism (EULAR) recommendations. Gout incidence, prevalence, morbidity and mortality, geographical variation of the disease, relevant risk factors for both the occurrence and outcome of gout and trends of the disease over time are then described. Difficulties in obtaining the information and data reported are also discussed.
Descriptive epidemiology
Gout is a crystal-deposition rheumatic disease. It is a more common inflammatory arthritis in men, characterised by formation of monosodium urate (MSU) crystals in the synovial fluid of joints and in other tissues. The crystals’ formation is caused by persistent urate levels in extracellular fluids (ascertained as serum uric acid levels) over the saturation threshold. Serum uric acid (sUA) is the endproduct of purine metabolism, in most cases, resulting from the inefficiency of renal urate excretion. Impaired renal excretion leads to the excess of sUA or hyperuricaemia, which occurs in 5–25% of the human population. About 10% of people with hyperuricaemia develop gout , and 80–90% of patients with gout are hyperuricaemic. The presence of MSU crystals has been considered as the gold standard for the diagnosis of gout since it was identified in the synovial fluid analysis reported in 1961 . The usual initial presentation of gout is with rapidly developing acute inflammatory monoarthritis, typically affecting the first metatarsophalangeal (MTP) joint (60%) . Up to 70% of patients with gout, who remained hyperuricaemic, were reported to develop radiographic signs of osteoarticular involvements .
Case definition
Two less common criteria used for the diagnosis of gout and referred to in clinical studies related to the disease were based on recommendations to two international symposia, held in Rome (1963) and New York (1966), sponsored by the Council for International Organizations of Medical Sciences (C.I.O.M.S.), established under the joint auspices of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the World Health Organization (WHO), with partial support from the National Institute of Arthritis and Metabolic Diseases and the Arthritis and Rheumatism Foundation . The two sets of criteria are presented in Table 1 . Two or more of the criteria in each set were required for the diagnosis. The New York (1966) criteria (published 1968) allowed the diagnosis of gout independently of these criteria, if synovial urate crystals were demonstrated.
| Rome (1963) Criteria | New York (1966) Criteria |
|---|---|
| 1. Painful joint swelling. Abrupt onset, clearing in 1–2 weeks initially | 1. Two attacks of painful limb joint swelling. Abrupt onset and remission in 1–2 weeks initially |
| 2. Serum uric acid: >7 mg in males, >6 mg in females | 2. An attack involving a great toe-as described in criteria 1 (above) |
| 3. Presence of tophi | 3. Presence of a tophus |
| 4. Presence of urate crystals in synovial fluid | 4. Response to colchicine-major reduction in inflammation within 48 h |
Since it was published, the diagnosis criteria and case definition for gout by the ‘1977 American Rheumatism Association (ARA) criteria’ have been more widely used and referred to in epidemiological and other studies related to gout, although the report clearly stated that they were preliminary criteria.
In 1977, after the data from more than 700 patients with gout, pseudogout, rheumatoid arthritis or septic arthritis were analysed, the criteria for classifying a patient as having gout were determined by the ARA subcommittee on classification criteria for gout. The criteria were reportedly intended for the diagnosis of acute arthritis of primary gout, but also included clinical and radiographic examinations for chronic gout. They were (1) the presence of characteristic urate crystals in the joint fluid, and/or (2) a tophus proved to contain urate crystals by chemical or polarised light microscopic means and/or (3) the presence of six of the 12 clinical, laboratory and X-ray phenomena listed below:
- (a)
maximum inflammation developed within 1 day;
- (b)
more than one attack of acute arthritis;
- (c)
monoarticular arthritis;
- (d)
redness observed over joints;
- (e)
first MTP joint painful or swelling;
- (f)
unilateral first MTP joint attack;
- (g)
unilateral tarsal joint attack;
- (h)
suspected tophus;
- (i)
hyperuricaemia;
- (j)
asymmetrical swelling within a joint on X-ray (this could be found logically on examination as well as on X-ray, but the study’s protocol did not include this information as part of the examination);
- (k)
subcortical cysts without erosions on X-ray; and
- (l)
negative organisms on joint fluid culture.
In the study’s analysis, sUA levels were analysed as a dichotomous variable; normouricaemia/hyperuricaemia. It was reported in the methods of analysis that hyperuricaemia was defined separately for each laboratory of the 38 centres across United States that contributed the data to the study. In principle, hyperuricaemia was defined as a level above the mean plus two standard deviations from the mean uric acid level for a healthy population, by the method used. The studied sUA level for hyperuricaemia was, therefore, not necessary the cut-off point of the saturation threshold.
The subcommittee also developed a related list of 11 criteria ascertainable in a single patient visit to a clinic or by history and review of clinical records such as in population surveys. The criteria for classifying a patient as having gout required the presence of 6 of 11 criteria. It was noted that joint aspiration was not needed for these proposed survey criteria. The criteria were:
- (1)
more than one attack of acute arthritis;
- (2)
maximum inflammation developed within 1 day;
- (3)
oligoarthritis attack;
- (4)
redness observed over joints;
- (5)
first MTP joint painful or swelling;
- (6)
unilateral first MTP joint attack;
- (7)
unilateral tarsal joint attack;
- (8)
tophus (proven or suspected);
- (9)
hyperuricaemia;
- (10)
asymmetrical swelling within a joint on X-ray (this could be found logically on examination as well as on X-ray, but the study’s protocol did not include this information as part of the examination); and
- (11)
complete termination of an attack.
Recent studies were carried out to test and validate the 1977 ARA criteria . It has been noted that several limitations of the criteria were yet to be resolved, fully validated and, therefore, still remained ‘preliminary’. Nevertheless, the 1977 ARA criteria for population surveys has been chosen as the case definition for gout, one of the diseases included in the Musculoskeletal Disorders and Risk Factors Expert Group (MSK EG), as a part of the Global Burden of Diseases, Injuries, and Risk Factors Study (the GBD 2005 Study).
In 2006, on behalf of the European League Against Rheumatism (EULAR), the multidisciplinary guideline development group has developed evidence-based recommendations for the diagnosis and management of gout. Ten key propositions ( Table 2 ) have been generated regarding the diagnosis using a combination of research-based evidence and expert consensus. The key propositions were including diagnostic topics in clinical manifestations, urate crystal identification, biochemical tests, radiographs and risk factors/co-morbidities. The evidence for diagnostic tests, risk factors and co-morbidities was evaluated and the strength of recommendation (SOR) was assessed using the EULAR visual analogue and ordinal scales. Although the SOR for each proposition varied according to the research evidence and expert opinion, it was generally high (greater than 80%), except for the proposition 8 (72%). It was noted that there were various limitations to the recommendations, including the omission of patient opinion, which is an important element of evidence-based medicine.
| Proposition |
|---|
| 1. In acute attacks the rapid development of severe pain, swelling, and tenderness that reaches its maximum within just 6–12 h, especially with overlying erythema, is highly suggestive of crystal inflammation though not specific for gout. |
| 2. For typical presentations of gout (such as recurrent podagra with hyperuricaemia) a clinical diagnosis alone is reasonably accurate but not definitive without crystal confirmation. |
| 3. Demonstration of MSU crystals in synovial fluid or tophus aspirates permits a definitive diagnosis of gout. |
| 4. A routine search for MSU crystals is recommended in all synovial fluid samples obtained from undiagnosed inflamed joints. |
| 5. Identification of MSU crystals from asymptomatic joints may allow definite diagnosis in intercritical periods. |
| 6. Gout and sepsis may coexist, so when septic arthritis is suspected Gram stain and culture of synovial fluid should still be performed even if MSU crystals are identified. |
| 7. While being the most important risk factor for gout, serum uric acid levels do not confirm or exclude gout as many people with hyperuricaemia do not develop gout, and during acute attacks serum levels may be normal. |
| 8. Renal uric acid excretion should be determined in selected gout patients, especially those with a family history of young onset gout, onset of gout under age 25, or with renal calculi. |
| 9. Although radiographs may be useful for differential diagnosis and may show typical features in chronic gout, they are not useful in confirming the diagnosis of early or acute gout. |
| 10. Risk factors for gout and associated co-morbidity should be assessed, including features of the metabolic syndrome (obesity, hyperglycaemia, hyperlipidaemia and hypertension). |
Recently, these EULAR recommendations were evaluated in a study on the diagnosis of chronic gout by Pelaez-Ballestas et al. (2010). The results showed that only 15% of the diagnosed patients had crystal-proven gout . Nevertheless, the recommendations have the advantage of including the reference to research data undertaken since the last published classification criteria in 1977.
In a published review by Dore (2008) , it was stated that in clinical settings where joint aspiration could not be performed, a clinical diagnosis of gout may be made in consultation with published recommendations and criteria from expert societies, for example, 1977 ARA criteria and EULAR recommendations. It was suggested that a thorough patient history and physical examination as well as sUA measurement at the time of an acute attack and at 2 weeks’ follow-up would be critical to the diagnosis.
Incidence
Published data on gout incidence were relatively limited compared with the reported prevalent data. The 5-year cumulative incidence (from 1991–1992 to 1996–1997) of 18.83% (42/223) for gout in China was reported by Lin et al. (2000) . The 11-year cumulative incidence rates in New Zealand Maoris were 10.3% for males and 4.3% for females . In the US, the cumulative incidence of gout was reported to be 8.6% in men . Over time, the incidence of gout in the US population was found to have increased from 0.03% in 1978 to 0.05% in 1996 .
An annual incidence of gout in Czech Republic was 0.41% . In the UK, a higher overall annual gout incidence of about 0.13–0.14% was reported , with 0.19% in men and 0.07% in women .
In aged Canadian population, it was reported that over 65 years of age, the incidence rates were 5.7–7.5/1000 person-years in men and 2.4–2.8/1000 person-years in women .
Prevalence
Gout is the inflammatory joint disease commonly seen in men. Overall, the range for prevalence of gout was from 0.03% (Nigerian men) to 15.2% (Taiwanese aboriginal men). On average, it was affecting about 1–2% of adult men in Western countries. In black Africans, gout was relatively rare, whereas the prevalence rates were very high in Aboriginal populations in Asia and Australasia. The prevalence of gout reported in different countries and regions of the world is listed in Table 3 .
| Country and Region | Prevalence (%) | ||
|---|---|---|---|
| Total | Men | Women | |
| Africa | |||
| Nigeria | 0.03 | ||
| Zimbabwe | 0.74 | ||
| Togo | 1.9 | ||
| Asia | |||
| India | 0.12–0.19 | 0.25–0.38 | 0 |
| Vietnam | 0.14 | 0.31 | 0 |
| Thailand | 0.16 | 0.26 | 0.07 |
| Pakistan | 0.23 | ||
| Georgia | 0.29 | 0.61 | 0.03 |
| Philippines | 0.59 | 0.47 | 0.72 |
| Japan | 0.14 | 0.27–1.1 | 0.03–0.08 |
| Java, Indonesia | 1.7 | ||
| China | 1.14 | 1.94 | 0.42 |
| Taiwan | 0.16–0.67 | ||
| Taiwanese aborigines | 11.7 | 15.2 | 4.8 |
| Australasia | |||
| Australian Aborigines, Australia | 7.0 | 0.9 | |
| Europeans, New Zealand | 2.9 | 5.8 | |
| Maoris, New Zealand | 6.4 | 8.8–13.9 | 0.8 |
| Tokelau | 0.14–0.19 | ||
| Tokelauan in New Zealand | 0.21–0.51 | ||
| Samoa | 2.3 | 1.3 | |
| Europe | |||
| Czech Republic | 0.3 | 0.49 | 0.08 |
| Scotland, UK | 0.34 | ||
| Italy | 0.46 | ||
| Spain | 0.48 | ||
| Greece | 0.5–0.85 | 0.8–1.28 | 0.18–0.44 |
| Germany | 1.4 | ||
| UK | 1.4 | 2.2 | 0.6 |
| Sweden | 1.3 | 1.4 | 1.2 |
| Middle east | |||
| Kuwait | 0.03 | ||
| Iran | 0.13 | 0.18 | 0.04 |
| North America | |||
| Alaskan Inupiat Eskimo | 0.3 | ||
| USA | 0.47–0.52 | ||
| South America | |||
| Cuba | 0.38 | 0.48 | 0.31 |
| Mexico | 0.4–0.7 | 0.68–1.05 | 0.15–0.26 |
Morbidity
The inefficiency of renal function was directly associated with the development of gout. In chronic gout, 86.3% of patients with renal impairment were reported . Urolithiasis was reportedly diagnosed in 35–39% of the studied patients with primary gout . In a cross-sectional analysis of gout and urolithiasis, the prevalence of urolithiasis was almost twofold higher in men with a history of gout compared with those without (15% vs. 8%) . Forty-seven percent of the patients with primary gout were reported to have musculoskeletal (MSK) disability and 31% had renal failure. The presence of tophi, hypertriglyceridaemia and history of ischaemic heart disease (IHD) were associated with MSK disability and renal failure was associated with patient age .
While hyperuricaemia slightly increased the risk of coronary heart disease , gout was found to be associated with cardiovascular diseases (CVDs) (angina pectoris, myocardial infarction, heart failure, cerebrovascular accident, transient ischaemic attack and peripheral vascular disease) and with cardiovascular risk factors (hypertension, diabetes mellitus, obesity and hypercholesterolaemia) . A case-control study in the Dutch population reported 35% of gout patients with one or more prevalent cardiovascular diseases. A 2-year retrospective study examining co-morbidities and medication use among patients with gout/hyperuricaemia across the United States reported that 57.9% had hypertension, 45.3% had a lipid disorder, 32.5% had both conditions and 19.9% had diabetes mellitus . Similar co-morbidities were also seen in gout patients in other regions of the world, such as northern Thailand . The results of a more recent cohort study showed an approximate 2:1 prevalence ratio of essential hypertension, hyperlipidaemia, diabetes mellitus without complications and coronary atherosclerosis in patients with gout when compared with those without . Compared with patients with osteoarthritis, gout patients were more likely to have cardiovascular disease, hypertension, diabetes and chronic renal failure (CRF) .
Elevated sUA levels were reported to have a strong association with metabolic syndrome (MS) . The prevalence of MS was reported to be 62.8% among gout patients and 25.4% among patients without gout . A study on the temporal relationship between the first gout attack and the diagnosis of MS, its components and complications found that first attacks of gout may precede the diagnosis of metabolic abnormalities and associated diseases . In 90% of the studied patients, the first attack of gout preceded the diagnosis of features of MS, MS itself or its complications including IHD and CRF. At the time of entering the study, 93% of the patients had at least one associated disease. The most common were hypertriglyceridaemia, 63%; obesity, 54%; hypertension, 45.6%; MS, 40%; hyperglycaemia, 37%; low high-density lipoprotein (HDL), 17%; diabetes, 15%; CRF, 17%; and IHD, 6.6%.
After over 2 years of follow-up, Su et al. (2008) reported 6.9% incidence of renal function deterioration (RFD) in a population of male gout patients. The age at disease onset, disease duration, treatment duration, family history of gout, tophi, urolithiasis, smoking, alcohol consumption, history of cerebral vascular accident, hypertension, diabetes mellitus, dyslipidaemia, creatinine (Cr) levels, blood urea nitrogen level, sUA level and body mass index (BMI) were identified as associated risk factors for RFD. History of IHD and greater waist circumference (WC) were the two independent risk factors for developing RFD.
Mortality
An association between hyperuricaemia and cardiovascular mortality is evidenced. Tomita et al. (2000) conducted a prospective cohort study to investigate the relationship between hyperuricaemia and health hazards in a Japanese population. During an average 5.4-year study period, subjects with sUA > 8.5 mg dl −1 showed elevated relative risks (RRs) of death in all causes (RR 1.62), coronary heart disease (RR 1.52), stroke (RR 2.33), hepatic disease (RR 3.58) and renal failure (RR 8.52), when compared with those with sUA levels of 5.0–6.4 mg dl −1 . The RR of death in all causes remained statistically significant when adjusted by age and serum total cholesterol (RR 2.00), age and alcohol intake (RR 1.85), age and smoking (RR 1.69), age and gout treatment (RR 1.61) and also age and BMI (RR 1.50). The results showed a strong association between hyperuricaemia and the RRs of death in all causes, coronary heart disease, stroke, hepatic disease and renal failure. A prospective study with 10-year follow-up by Aboa et al. (2001) reported significant correlations between hyperuricaemia and all-causes mortality in men, while a tendency was observed in women. A similar pattern was also observed for cardiovascular mortality. A recent review published by Kim et al. (2009) concluded that hyperuricaemia increased the risk of both stroke incidence and mortality . From these findings, hyperuricaemia was a considerable risk factor for reduced life expectancy.
In men who had gout, the increased mortality risk was primarily due to an elevated risk of cardiovascular death, particularly from coronary heart disease. A 17-year follow-up study by Krishnan et al. (2008) showed that among middle-aged men, a diagnosis of gout accompanied by an elevated sUA level was a significant independent CVD mortality risk. The unadjusted mortality rate from CVD in middle-age men with gout was 10.3 per 1000 person-years, representing approximately 30% greater risk when compared with 8.0 per 1000 person-years in men without gout. After adjusting for other known risk factors, use of diuretics and aspirin and serum creatinine level, the hazard ratios (HRs; gout vs. no gout) were 1.35 for coronary heart disease mortality, 1.35 for death from myocardial infarction; 1.21 for death from CVD overall; and 1.09 for death from any cause.
In a more recent prospective cohort study, Chen et al. (2009) reported that during an average 8.2-year follow-up period, HRs for hyperuricaemia (sUA > 7 mg dl −1 ) were estimated after adjusting for age, sex, BMI, cholesterol, triglycerides, diabetes, hypertension, heavy cigarette smoking and frequent alcohol consumption. In all patients, the HRs were 1.16 for all-cause mortality, 1.39 for total CVDs and 1.35 for ischaemic stroke.
Geographical variation
Geographical difference in occurrence/outcome of gout
Variation of the occurrence/outcome of gout due to geographical difference is described below. In addition, within similar geography, some variation of the disease was also presented.
Africa
Gout in black Africans was considered relatively rare. The hospital admission rate of gout patients seen in black South Africans from 1977 to 1981 was 0.005% . The disease was the most common inflammatory joint disease seen in in-patients in West Africa and Equatorial Africa . Gout prevalence of 0.03% was reported in Nigerian men . In black Zimbabweans of Gweru City, gout prevalence was 0.74% . An unusually high gout prevalence of 1.9% was reported in Togolese patients admitted to the Lome Teaching Hospital in Togo .
Asia
In Taiwan, gout prevalence in the rural population was 0.16%. A similar prevalence rate of 0.67% was reported in both suburban and urban populations . High gout prevalence in Taiwanese aborigines was reported to be 11.7% , with 15.2% in men and 4.8% in women . Gout prevalence was significantly higher in men when compared with women (1.94% vs. 0.42%) in the population recruited from five coastal cities (Qingdao, Rizhao, Yantai, Weihai and Dongying) of Shandong province in Eastern China . Another population-based cross-sectional survey in the coastal city of Qingdao reported the age-standardised prevalence of 0.36% for gout in adults aged 20–74 years . In Huangpu District of Shanghai, gout prevalence for men was reported to be 0.77%, with the rate of 0.34% for both men and women . In the rural area of Shanghai, gout prevalence was 0.28% , and the age–sex standardised rate of 0.22% was reported in an urban population .
Community Oriented Program for the Control of Rheumatic Diseases (COPCORD) studies reported 0.14% of gout prevalence in an urban population in Vietnam , 0.16% in rural Thailand , 0.19% in Jammu, India and 0.59% in a remote village area of the Philippines . A lower prevalence rate was reported in a rural population in village Bhigwan (Dist. Pune), Western India. Gout was diagnosed in 0.12% in the studied population, and no case was found in women . In north Pakistan, there was no case reported in the rural population, whereas gout prevalence of 0.23% was reported in the urban population . The prevalence of gout and hyperuricaemia in men was 1.7% and 24.3%, respectively, in the rural population of Java, Indonesia. The male to female ratio was 34:1 for gout and 2:1 for hyperuricaemia . In Japan, epidemiological data for the prevalence of gout were limited. Data published in 1980s showed a 0.27% prevalence of gout in men and 0.03–0.08% in women . A more recent study reported a prevalence of 1.1% in Japanese men .
In Georgian Soviet Socialist Republic, Central Asia, 0.29% of gout prevalence was reported. Most of the studied population was men aged over 40 years with hereditary predisposition, obesity, carbohydrate metabolic derangement and consuming food rich in purine bases, national flavourings and spices .
Australasia
In an Australian Aboriginal community in North Queensland, Australia, the cumulative prevalence of gout was 7.0% in men and 0.9% in women over the age of 15 years . Comparable prevalence rates were reported in New Zealand Maoris, where the prevalence of gout was 8.8% for males and 0.8% for females . In a study comparing Maoris and Europeans in New Zealand, gout prevalence in Maoris was 6.4% compared with 2.9% in Europeans, with 13.9% in Maori men and 5.8% in European men .
Higher rates of the age-standardised prevalence of gout in Tokelauan men in New Zealand (0.21% in 1968 and 0.51% in 1982) were reported when compared with those in non-migrant Tokelauan men living on the island (0.19% in 1968 and 0.14% in 1982). The prevalence of gout was reportedly low in women in both environments . In Western Samoa, the prevalence of gout was 2.3% in men. The prevalence of 1.3% was seen in women living in the urban area, and none was found in the rural women .
Europe
A survey of the prevalence of chronic arthritic conditions in four geographical areas of the highlands of Scotland reported 0.34% of gout prevalence . In a descriptive population-based survey, gout prevalence of 0.3% was reported in Czech Republic . In an Italian population sample, the results of a regional community-based study showed 0.46% of gout prevalence . In Spain, the prevalence in an urban population of 15 years and older was 0.48% . In Greece, the prevalence rates of gout of 85%, 0.5% and 0.5% in the urban, suburban and rural populations, respectively, were reported . A similar gout prevalence rate of 1.4% was reported in the UK and Germany , with 2.2% in men and 0.6% in women reported in the UK population . Obesity was the most common co-morbidity in the UK (27.7%), while diabetes (25.9%) was the most common co-morbidity in Germany. In aged Swedish population, gout prevalence was reported to be 1.3% at the age of 79 years .
Middle east
In Saudi Arabia, 8.42% of the study population had hyperuricaemia, but no case of gout was found . A low prevalence of 0.03% was reported in the COPCORD study of Kuwaiti nationals aged 15 years and over . A large urban COPCORD study in Iran showed 0.13% of gout .
North America
In the US, data extracted from the Integrated Healthcare Information Services (IHCIS) claims database between 1999 and 2005 showed, that in the population aged 65 years or older, gout was predominantly seen in males (73.5%) . Data collected from multiple large employers with employees widely dispersed across the US from 2000 to 2004 showed that the annual prevalence of gout was 0.47% . A lower gout prevalence of 0.3% was reported in an Alaskan Inupiat Eskimo population .
South America
The rural population in Yucatan, Mexico was reported to have a gout prevalence of 0.7% . In Mexico City, a COPCORD study reported 0.4% gout prevalence, with a range from 0.1% to 0.7% . A COPCORD study in an urban community in Havana City, Cuba, reported a gout prevalence of 0.38% .
What are the reasons?
Geographic or ethnic differences/similarities in the occurrence of disease could provide insights into causes of disease and possible strategies for disease prevention. Race, diet and lifestyle such as physical activity and drinking habit and urbanicity could be established as having influence on geographical difference in the development of hyperuricaemia and gout. It is evidenced by the published findings described below.
Race
Among the aboriginal populations, including Australian Aborigines, New Zealand Maoris and Taiwanese aborigines, gout prevalence was reported to be high . The remarkably high prevalence of gout and hyperuricaemia in Taiwanese aborigines was evidently found to be associated with a genetic basis for familial gout .
In New Zealand, gout was significantly more common in Maoris (6.4%) than Europeans (2.9%), and in Maori men (13.9%) than in European men (5.8%). Hyperuricaemia was significantly more common in Maori men (27.1%) than in European men (9.4%) and in Maori women (26.6%) than in European women (10.5%). Clinical differences included a stronger family history, earlier age at onset and a higher frequency of tophi and polyarticular gout in Maoris than Europeans . It was also reported that, in Maoris, there was a significant link between muscle size and the incidence of gout in men. Other risk factors associated with gout in Maori men were body mass and blood pressure . In addition, obesity, commonly seen among the Maoris, could also accentuate their natural tendency to hyperuricaemia and gout .
Although the same characteristics of the disease were presented as those reported in Caucasians, a lower frequency of diabetes mellitus was seen in a South American Guatemalan population . In this Guatemalan population, mean sUA was higher than 7.0 mg dl −1 in 60% of the patients, and the occurrence of the disease peak prevalence in the fifth decade was seen in 26%. A similar period of the occurrence was also reported in Japanese gouty patients . In the Chinese–Taiwanese population, the first attack frequently occurred between the third and fifth decades (68.2%) rather than between the fourth and sixth decades . In addition, the studied patients had more frequent gouty attacks and the interval from the first attack to visible tophi was shorter than in other studies previously reported in Caucasians .
Within Caucasians, gout attack was reported to occur during different seasons of the year. In American patients, acute gout attack was most common during spring (32%). Twenty-five percent of the patients had acute gout attacks in the fall, 23% had acute attacks during the summer and 20% had acute attacks in the winter . In Italy, the first gout attack was reported to occur mainly in the months of June and July (summer) and December (winter) .
Diet, lifestyle and urbanicity
Even though gout was considered rare in urban, black South Africans, changing dietary habits and a more modernised lifestyle, together with improving socioeconomic conditions, were found to be contributing significantly to the increasing prevalence of the disease . The increase of gout prevalence seen in Japanese population was linked to the epidemic of obesity (BMI ≥ 25 kg m −2 ), possibly due to decreasing physical exercise . It was apparent that with increasing obesity, gout has become endemic in China . In the Chinese population, hyperuricaemia and gout were associated with dietary and lifestyle changes. Urban residents showed a much higher prevalence of hyperuricaemia compared with rural residents (14.9% vs. 10.1%). Similarly, higher prevalence was noted in a developed city compared with a less developed city (18.02 vs. 5.3%). These differences were highly correlated with economic development, as manifested by the increase of daily consumption of meat and seafood .
An urban Taiwanese population showed higher prevalence of gout compared with the rural population (0.67% vs. 0.16%) . A similar pattern of gout prevalence (0.85% vs. 0.5%) in the urban and rural populations was also seen in Greece . A significantly lower prevalence of gout in rural areas compared with urban cohorts in black Africans has led to the suggestion that environmental factors associated with urbanisation may influence the disease pathogenesis . In the Polynesian population of Western Samoa, prevalence of gout was similar for men in urban and rural areas (2.3%). Gout prevalence of 1.3% was seen in women living in the urban areas and there was no case reported for women in the rural areas . In north Pakistan, gout prevalence of 0.23% was reported in the urban population but no case was seen in the rural population . The age-standardised RR of developing gout between 1968 and 1982 was reported to be 9.0 times higher in the migrant Tokelauan men in New Zealand than that in non-migrant Tokelauan men living on their isolated island .
The RR of gout associated with drinking regularly was 2.5, and with BMI > 25 kg m −2 was 3.3 in an Australian Aboriginal community in North Queensland, Australia . Similar to other African and Western countries, in black South Africans, Togo and Guatemala, the main risk factors for gout were excessive alcohol consumption, overweight and obesity and hypertension .
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
