Why Is Diabetes More Common in the USA than in the UK?

Type 2 diabetes is almost twice as prevalent in middle-aged and older Americans as in their English counterparts. It’s diagnosed in 11% of English males vs. 16% American males;  in women, the corresponding rates are 7% vs. 14%.  Researchers at University College, London and the RAND Corporation, California have determined the reason for this difference, and published their findings online in the Journal of Epidemiology and Community Medicine.

Data from large samples of non-minority adults aged 52 to 85 were taken from the NHANES study (1999-2006) in the USA and the English Longitudinal Study of Aging (2004).  They included self-reported and objective disease markers for diabetes, as well as major risk factors for diabetes, including measures of body mass index (BMI), height, and waist circumference.

There were no significant differences in lifestyle between the two groups.  For instance, the BMI, smoking prevalence, and socio-economic status, as well as the conventional type 2 diabetes risk factors were fairly similar in both countries.  However, the average waist circumferences were 3 cm larger in the US men, and 5 cm larger in the US women, than those of their English counterparts.  Importantly, the US group had a significantly higher waist circumference across the different BMI categories, showing the apparent specificity of the relationship between waist size and diabetes.  Calculations showed that higher waist size explained the difference in 75% of cases in the men, and in 38% of cases in the women. 

What are the reasons for the differences in waist sizes in the two countries?  The researchers have several possible explanations:  Americans are less physically active than the English; the American diet is more likely to result in the laying down of intra-abdominal fat; and the levels of everyday stress may be different in the two countries.  Finding the relevant cause will be important, if we are to make inroads into the diabetic epidemic in the USA.  And it might help in fighting obesity, too.