Diabetes in the Torres Strait Islands of Australia: better clinical systems but significant increase in weight and other risk conditions among adults, 1999-2005

Objectives: To (i) assess changes in clinical indicators of adults diagnosed with diabetes and (ii) estimate changes in risk factors and incidence of diabetes among adults without diabetes living in the Torres Strait and Northern Peninsula Area Health Service District in Queensland from 1999 to 2005. Design and participants: (i) Annual audit of clinical records of Torres Strait Islander adults on diabetes registers in 21 primary care clinics, and (ii) a 5-year follow up of a community cohort of 207 Torres Strait Islander adults without diabetes who participated in the Well Person's Health Check in 2000-01 and 2005-06. Main outcome measures: Weight, height, waist circumference, fasting blood sugar (those without diabetes) and glycated haemoglobin (HbA(1c); those with diabetes) levels, blood pressure (BP), fasting triglyceride and high-density lipoprotein cholesterol levels, urinary albumin-to-creatinine ratio and smoking status. Results: The number of adults included on the diabetes register increased from 555 in 1999 to 1024 in 2005. The mean age of patients diagnosed with diabetes decreased from 53.3 to 51.5 years, and their mean weight increased from 86.8 kg to 95.6 kg. Mean HbA(1c) level remained unchanged at about 9%, but the proportion with HbA(1c) level < 7% increased from 18.4% to 26.1%, and the proportion prescribed insulin increased from 14% in 2002 to 22% in 2005. The proportion with BP < 140/90 mmHg increased from 40.3% in 1999 to 66.8% in 2005. In the sample of 207 adults without diabetes, from 2000 to 2006, there was a weight gain of about 1 kg per person per year, and an annual increase in waist circumference of 0.8 cm in men and 1.2 cm in women. Crude incidence of diabetes was 29 (95% CI, 19-41) per 1000 person-years. There was a significant increase in diastolic blood pressure and fasting blood sugar levels, and no change in smoking habits. Conclusions: Clinical care of adults with diabetes has improved and more people with diabetes are being diagnosed. However, weight gain and high rates of glycaemia remain a challenge and will result in a large burden of complications, including renal failure. Incidence data from this sample extrapolate to 120 (95% CI, 103-147) new cases of diabetes in the District each year. Urgent action to improve nutrition, decrease smoking and increase physical activity is required to improve metabolic fitness in younger people.