WASHINGTON - New research, based on a long-running British study, offers a partial explanation for a trend that is firmly established in industrialized democracies - that where calories are plentifully available, those on the lower rungs of the economic ladder are most likely to develop Type 2 diabetes. The study was published Tuesday in the open-access journal Public Library of Science (PLoS) Medicine.

The "Whitehall II" study tracked 6,387 London-based civil servants, who were between 35 and 55 years old when they were recruited, for as long as 24 years starting in 1985. Roughly every two years, researchers weighed subjects, administered glucose tolerance tests, inquired about diabetes diagnoses and health behaviors, and drew blood samples.

The researchers also set out to establish where subjects fell on the socioeconomic ladder, and whether their status had risen or fallen over their lives.

Those on the lower rungs were more likely to develop Type 2 diabetes than those with more education and rosier economic circumstances. They also had poorer health behaviors compared to those in higher positions with more education.

But irrespective of such behaviors, the participants with lower lifetime socioeconomic status also showed higher levels of inflammation in their blood.

And even after researchers adjusted for the effects of smoking, lack of exercise and bad diets (all of which would push inflammatory levels up), higher levels of inflammation among those on society's lower rungs explained close to a third of the diabetes cases.