Low paid civil servants were more likely to develop type 2 diabetes

London civil servants at the lower end of the employment scale and with lower social position were more likely to develop type 2 diabetes than those at higher employment levels, according to an article in the September 27 issue of the Archives of Internal Medicine, one of the JAMA/Archives journals.

According to the article, recent studies have described a significant inverse relationship between impaired glucose tolerance (an indication of diabetes) and grade of employment in the civil service. Also, American adults with type 2 diabetes have less education and lower income than those without the disease. Psychosocial factors, such as having little control at work, low social support, depression and effort-reward imbalance (when high effort at work produces little reward or benefit), are established risk factors for coronary heart disease (CHD), which shares several common features with type 2 diabetes.

Meena Kumari, Ph.D., of University College London, and colleagues examined the relationship between social position and incidence of type 2 diabetes and whether psychosocial risk factors for CHD are associated with the onset of type 2 diabetes.

The researchers studied 10,308 civil servants aged 35 to 55 years during phase 1 of the Whitehall II Study (1985-1988). The Whitehall II study was established to examine relationships between social position, health, and death. Questionnaires were used to determine diabetes status at the beginning of the study and at phase 2 (1989), phase 3 (1992-1993), phase 4 (1995), and phase 5 (1997-1999), and glucose tolerance tests were administered at phase 3 and 4.

Employment grade was divided into three categories: administrative (the seven highest paying grades), executive (including senior executive officers, higher executive officers, executive officers and other professional and technical staff receiving similar salaries), and clerical (including clerical and office support grades). Participants also answered questions regarding family history of diabetes, coronary risk factors (including smoking, alcohol consumption, exercise habits and diet), and psychosocial questions regarding work, social support, depression, and relationships.

The researchers found that over an average follow-up time of 10.5 years, 4 percent of the participants (242 men and 119 women) developed diabetes. Men working in lower employment grades had almost three times the risk of developing diabetes, and women had a 70 percent higher risk of developing diabetes than participants in higher employment grades. Participants whose body mass index (BMI) indicated overweight (BMI, 25.0-29.9) or obesity (BMI, 30 or greater) were at increased risk of diabetes. Among the psychosocial risk factors examined, only effort-reward imbalance was associated with diabetes, and only in men, who had a 70 percent greater chance of developing diabetes if they reported experiencing effort-reward imbalance.

"We have demonstrated that there is a social gradient in incidence of type 2 diabetes in middle-aged men and women in white-collar occupations," write the researchers. "In addition, we show that effort-reward imbalance is associated with incidence of type 2 diabetes in men only."