Prevalences of overweight, obesity, hyperglycaemia, hypertension and dyslipidaemia in the Gulf

Prevalences of overweight, obesity, hyperglycaemia, hypertension and dyslipidaemia in the Gulf

Reported, January 10, 2012

The increasing prevalence of diabetes mellitus, particularly type 2 diabetes mellitus, is well documented.Type 2 diabetes is currently estimated to account for over 90% of the global diabetes burden.Together with similar trends in other non-communicable diseases, it leads to risks not only for individuals, but for health systems, social systems, and state economies. This risk is in part to do with an anticipated relatively dramatic rise in countries with relatively young populations, and still developing economic infrastructure, as they undergo the predicted increases in prevalence of diabetes associated with changes in lifestyle and economic development, and population growth. Even when based on changes in population size and demography alone,3 the highest predicted future increases are expected in the International Diabetes Federation’s ‘African’ region (estimated 98.1% increase 2010–2030), followed by the ‘Middle East-North Africa’ region (estimated 93.9% increase 2010–20304). The Middle East-North Africa region already has some of the highest rates of diabetes in the world. The countries of the Co-operation Council for the Arab States of the Gulf (GCC) include those currently ranked 2, 3, 5, 7 and 8 for diabetes prevalence among the 216 countries for which data are available.
This high prevalence in the GCC states is associated with higher prevalences of risk factors for type 2 diabetes in this region. The International Diabetes Federation suggests the following as risk factors for type 2 diabetes: age, obesity, family history, physical inactivity, race and ethnicity, and gestational diabetes. Of the modifiable risk factors, physical inactivity appears to have been surprisingly little studied in this region, although it is likely to be correlated with overweight and obesity, which have been relatively well studied.
We aimed to review the prevalence of overweight and obesity in the GCC region. We also aim to review the prevalence of potentially ‘pre-diabetic’ hyperglycaemia (measured either as impaired fasting glycaemia, impaired glucose tolerance or raised random glucose). We also examined hypertension and dyslipidaemia, which are risk factors for adverse outcomes in people with diabetes.Diabetes is complicated by various micro- and macro-vascular conditions and people with metabolic syndrome – a collective of obesity, insulin resistance, dyslipidaemia, hypertension and hyperglycaemia have a relatively higher prevalence of cardiovascular disease than those without.Due to the heterogeneity of studies identified on preliminary searching, there was no anticipated meta-analysis.

Forty-five studies (43 papers) relating to risk factors and their prevalence were identified for review. All papers identified were journal articles published between 1987 and 2010. Five studies were carried out (where reported) and/or published in the late 1980s, 23 in the 1990s, and 15 in the last 10 years. Studies of various 20 Saudi,24–46, seven Kuwaiti,47–50 three Bahraini,51–53 eight Emirati,54–60 four Omani61–64 and one Qatari65 populations were included. All were cross-sectional studies; 23 of the general population, seven of primary care populations, four of schoolchildren, three of students, one of a young population, five of working populations. Women were exclusively studied in five cases, men in six. Sample size ranged from 215 to 25,337.
In addition to examining the prevalence of the particular risk factors in the GCC states, we were interested in the following:
Trends in prevalence across time;
Differences by country;
Trends in prevalence associated with age;
Sex differences;
Location (urban/rural) differences;
Prevalence in children.
Only in the cases of overweight and obesity, and hyperglycaemia were study numbers sufficient that reasonable conjecture regarding subgroups could be made. They are considered separately, for each risk factor, below.

Obesity/overweight
Thirty-three studies addressed the prevalence of overweight/obesity

Overweight and effect of date and country

The reported prevalence rates of overweight (BMI 25 to <30) in adults ranged from 26.3–48% in men, and 25.2–35% in women. Although higher values are displayed in Table 1, they have been scaled down for/omitted from comparison as either the definition of overweight used included the typical definition of obesity, or the prevalence was given only by age group, allowing the possibility that similarly high figures were masked in the age-non-specific data of other studies. A lower value has also been omitted where the study population was particularly young.Within these ranges, the data were fairly even distributed between the limits, and reported sex-non-specific prevalences were also consistent with these figures. The data showed no obvious trends or anomalies by date or country, although the data from Oman (two studies, reporting combined overweight/obesity rates) suggest prevalence there may be relatively low.
Obesity and effect of date and country

The reported general prevalence rates of obesity (defined as BMI = 30) in adults ranged from 13.05–37% in men, and 15% in women (again a lower value has been omitted where the study population was particularly young). As for the overweight data, the reported sex-non-specific data are consistent with these figures, and potentially excepting the Omani data, show no obvious trends or anomalies by date or country.

Obesity and overweight and age

Age as a potential predictor of prevalence of overweight/obesity was considered in eight studies (of adult populations), and the results were tested for significance in two cases. These latter studies demonstrated correlation between overweight/obesity and age,and a significantly higher mean BMI in a year age group versus a year age group.Similarly, all remaining studies indicated that prevalence increased with age to a threshold level (variably between 30–40 and 50–60 years (potentially younger in women) after which it began to fall, or fluctuate.

Obesity and overweight and sex

Most studies reported prevalence rates by sex, but only four tested for differences. Of these four, in all cases but one, BMI/prevalence of obesity and overweight was higher in women,and where overweight was higher in men,the combined prevalence of overweight/obesity remained higher in women. In the remaining studies, prevalence of obesity, and the combined prevalence of overweight/obesity was again always higher in women, although in some cases the ‘difference’ was slight.

Obesity and overweight and residential environs

Six studies considered prevalence in urban versus rural populations. In three, mean BMI was found to be significantly higher in rural populations.In a further two studies, prevalence of both overweight and obesity were significantly lower in rural regions.This trend (with one subgroup exception – female obesity) was also observed where significance of differences was unclear.
Obesity and overweight in national/expatriate populations
Only one study considered prevalences in national versus expatriate populations. This reported that the combined prevalence of obesity and overweight was higher in Kuwaitis versus non-Kuwaitis.

Obesity and overweight in children

In keeping with the association with age, prevalences in children/young people (<20 years) are lower than those in adult populations. However, there is a greater indication that prevalences in the younger populations are increasing. Single figure prevalences were reported until around 2000, and have not been observed since. The most recent reports (suggesting prevalences of combined overweight and obesity >30%) provide rates comparable to those in adults. Although less considered, there is again evidence for higher prevalences with increasing age in these relatively young populations, in urban areas and in girls.

Hyperglycaemia

Seventeen studies reported on the prevalence of hyperglycaemia, studies as impaired glucose tolerance,three studies as impaired fasting glucose or a high random capillary glucose (>10 mmol/L). Generally, impaired glucose tolerance was defined as venous plasma glucose =7.8 and <11.1 mmol/L 2 h post glucose loading. Where the World Health Organization 1980 criteria were used, however, the impaired glucose tolerance would be defined as venous plasma glucose 8.0 and 11.0 mmol/L 2 h post glucose loading, and the study of Al-Moosa et al.62 involved capillary whole blood rather than venous plasma samples . Impaired fasting glucose was consistently defined as a fasting venous plasma glucose =6.1 and <7.0 mmol/L. The studies of random capillary blood glucose and impaired fasting glucose are so few that interpretation is difficult. Additionally, the random glucose measurement figures are likely to include instances of transient/‘stress’ hyperglycaemia. Nevertheless, both are potentially consistent with the impaired glucose tolerance results.

It was found the prevalence of overweight to be 25–50%, obesity 10–50%, relatively high in women and higher with advancing age to threshold levels between 30–40 and 50–60 years. Prevalence was also found to be high in children, and appeared to be increasing in this group. We estimated, from relatively recent reports, the prevalence of hyperglycaemia in adults (using impaired glucose tolerance as the outcome measure) to be approximately 10–20%. Prevalence of hyperglycaemia appears to have been increasing across recent years, and higher prevalence again showed an association with advancing age and female sex. There has been relatively little research of the prevalences of hypertension and dyslipidaemia in the GCC region and a lack of consistency in definitions used for study. Accordingly, estimates of prevalence vary: between 6.6–33.6% for hypertension, between 2.7–51.9% for dyslipidaemia, and it is unclear what additional factors may have impacted on these ranges.
Potentially, the prevalences of hypertension and dyslipidaemia are increasing, which would be in keeping with a more widespread trend.The increasing prevalence of hyperglycaemia is similarly in keeping with trends reported elsewhere. By contrast, we observed no obvious temporal trend in prevalence of overweight and obesity in adult populations, which is not in keeping with reports from elsewhere, and despite a relatively well established association with diabetes (both epidemiologically and pathophysiologically) and pathophysiologically. Importantly, though, particular authors have noted a rising prevalence within the relatively well controlled environments of their own studies,and several of the reviewed studies did demonstrate correlation between BMI, and overweight and obesity, and diabetes or blood glucose concentration.Moreover, the observed prevalence of overweight and obesity by age, increasing with advancing age until a plateau or decline in middle and older age, is suggestive that overweight and obesity may be an important risk factor for diabetes.
We noted differences in the patterns of spread of diabetes and obesity and overweight in the GCC region. For example, the observed bias of obesity and overweight to the female population is not obviously replicated in the population distribution of diabetes (unpublished data), demonstrating that additional aetiological factors may hold important roles in the current expansion of the diabetes problem.

Credits:
Layla Alhyas,Ailsa McKay,Anjali Balasanthiran,and Azeem Majeed1

More Information:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3147233/?tool=pubmed