A diet based on the traditional Mediterranean diet can improve glycemic control without causing weight gain in patients with well-controlled diabetes, an Australian study suggests.

“The intervention resulted in a statistically and clinically significant improvement in glycemic control, equivalent to mono drug therapy,” say Catherine Itsiopoulos, from the University of Canberra, and colleagues.

They also highlight that “in contrast to the commonly held view that a high-fat diet leads to weight gain, we demonstrated that a Mediterranean-style intervention diet, provided ad libitum with 40% energy from fat, did not cause weight gain. Indeed, a trend toward weight loss was observed.”

The team recruited 27 Australian-born patients with diabetes adequately controlled by diet (n=9), oral hypoglycemics (n=15), or insulin (n=3), and with no previous exposure to a Mediterranean diet.

The patients, who were were aged between 44 and 77 years, were randomly assigned to receive the intervention Mediterranean diet, consisting of plant foods, whole grains, and olive oil, or their usual diet for 12 weeks, followed by a crossover to the alternative diet for a further 12 weeks.

Body composition, markers of glycemic control, lipid levels, and biomarkers of dietary adherence, such as plasma carotenoid and fatty acid (FA) levels, were assessed at the end of both dietary periods.

The Mediterranean diet appeared to improve glycemic control, with glycated hemoglobin levels falling from 7.1% when patients consumed their usual diet to 6.8% when they consumed the Mediterranean diet (p=0.012).

Diet quality also improved, as illustrated by an increase in the patients’ plant to animal food ratio, from an average 1.3 on the usual diet to 5.4 after 12 weeks on the Mediterranean diet (p<0.001).

The patients’ mean body mass index (BMI) and homeostasis model assessment of insulin sensitivity (HOMA) score also improved, from 30.3 kg/m² and 6.1, respectively, when they consumed their usual diet to 30.0 kg/m² and 5.2, respectively, after 12 weeks on the Mediterranean diet.

Of note, the patients’ lipid profiles also improved while on the Mediterranean diet, with a 15% increase in monounsaturated FAs (p=<0.001) and a 17% decrease in trans and saturated FAs (p=0.001) compared with during their normal diet.

Writing in the journal Nutrition, Metabolism & Cardiovascular Diseases, Itsiopoulos et al conclude: “Despite major differences from their usual diet, subjects reported very positively both on their enjoyment of the Mediterranean-type diet and on how well they felt while consuming this diet.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

Free abstract

The increasing prevalence of Type 2 diabetes in England over recent years is linked to greater socio-economic inequality in women, but not men, report UK researchers.

Type 2 diabetes affects all socio-economic groups, but has been observed to be more common in lower socio-economic groups.

Anne Imkampe and Martin Gulliford from King’s College London explained: “We specifically aimed to determine whether socio-economic inequalities in diagnosed diabetes are reducing or increasing over time.”

The researchers analyzed data from the Health Survey for England collected in 1994, 1998, 2003, and 2006. Overall, 41,643 individuals aged 35 years or above were included in the study. The prevalence of self-reported, doctor-diagnosed diabetes in relation to household income, educational level, and occupational social class was assessed.

As reported in the European Journal of Public Health, the team found that the prevalence of diabetes in men and women in 1994 was 3.74% and 2.28%, respectively. By 2006, these values had increased to a corresponding 7.25% and 4.88%.

The authors found evidence for an association with socio-economic status in women, but not men, in 2006.

Women from the lowest social class, defined according to the Registrar General’s Classification, were 4.54 times more likely to have diabetes compared with women in the top social class in 2006. Similarly, women with little or no education (below GCSE level) had a 96% increase in relative risk compared with those who had achieved A-levels or above.

In addition, the Slope Index of Inequality for social class and level of education in women increased between 1994 and 2006, from -1.65 to -4.95 and from -1.39 to -6.48, respectively.

“There are several possible explanations for this finding,” say Imkampe and Gulliford. “Diabetes incidence could have increased disproportionately among lower socio-economic groups. Case ascertainment may have improved particularly in lower socio-economic classes.”

They add: “The finding may also be related to an increasingly ageing population with women living longer than men and the higher risk of poverty with older age, or to known inequalities in diabetes morbidity and mortality, improving treatment options for patients with diabetes and therefore potentially longer survival of people with diabetes in lower socio-economic classes.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

Free abstract

Results from a systematic review and meta-analysis confirm previous findings suggesting that variation in the heme oxygenase-1 gene (HMOX1) is linked to increased risk for Type 2 diabetes.

Previous studies have suggested that risk associated alleles of several variants of HMOX1, particularly a (GT)n repeat length polymorphism and the common single nucleotide polymorphism (SNP) T(-413)A, increase the risk for Type 2 diabetes, but other results have been conflicting.

To try and clarify the association, Liegang Liu (Huazhong University of Science and Technology, Wuhan, China) and colleagues carried out a systematic review and meta-analysis of five studies published before 2010 that included a total of 1965 Type 2 diabetics and 3484 controls.

All five studies genotyped participants for the (GT)n repeat length polymorphism and one also included the T(-413)A SNP.

The team found that carriers of the long (L) versus the short (S) allele of the (GT)n repeat length polymorphism had an overall 12% increased relative risk for Type 2 diabetes.

In addition, those with a LL genotype compared with a SS genotype for this variant had a 25% increased relative risk for Type 2 diabetes.

There was no evidence for an association between the T(-413)A genotype and risk for Type 2 diabetes, but the researchers acknowledge that there was only minimal data available for this polymorphism.

HMOX1 is thought to be a biomarker for cell stress status, which may explain the link with Type 2 diabetes.

“The results of this meta-analysis suggest that the HMOX1 (GT)n L allele may help to identify persons at higher risk of Type 2 diabetes; however, we do not suggest that such testing is indicated on a population-wide basis, because only a modest increase in Type 2 diabetes risk was observed,” write the authors, who suggest that further research on this topic is warranted.

The results of this study are published in the American Journal of Epidemiology.

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

Free abstract