A new study suggests that people with the “healthiest lifestyle” have a 75 lower risk of type 2 diabetes than those with the least healthy lifestyle. Published in Diabetologia (the journal of the European Association for the Study of Diabetes), amongst those individuals with type 2 diabetes, a healthy lifestyle is also associated with a lower risk of cardiovascular disease (CVD) and a lower risk of death from all causes, including CVD and cancer.
The number of people with type 2 diabetes globally has now been estimated at higher than half a billion, according to the latest Global Burden of Disease Study. There are 22 million new cases documented each year. Previous studies have shown that healthy lifestyle factors, such as physical activity, diet and weight management, are useful interventions in the prevention and management of type 2 diabetes.
Conducted by Dr An Pan and Mr Yanbo Zhang, Huazhong University of Science and Technology, Wuhan, China, and colleagues, the study aimed to evaluate the impact of combined healthy lifestyle factors; firstly on incidence of diabetes and secondly on morbidity and mortality outcomes in persons with the condition.
The authors looked for studies to include in their analysis that had a combination of at least three factors to indicate overall lifestyle, including smoking, drinking alcohol, physical activity/sedentary behaviour, diet, being overweight or obese, and sleep duration/quality. Follow up of at least a year was required for study eligibility. Baseline characteristics of the participants were extracted to adjust the data—age, gender, race and ethnicity, education level, health status.
Fourteen studies were identified for the main analysis, with 1,116,248 participants, and researches based in the USA, Asia, Europe, and Oceania (Australia, New Zealand and adjacent islands).
Mean baseline age ranged from 38 to 73 years; mean follow up was 2.7 to 20.8 years. A further 10 studies were used in the meta-analysis of people who already had type 2 diabetes, with 34,385 diabetic participants from researches based in USA, Asia, and Europe, and one global study across several continents. The mean age at baseline ranged from 46 and 69 years; with a mean follow up duration of 4 to 21 years.
For each of the 14 studies, healthiest versus unhealthiest lifestyle was assessed in a slightly different way (usually with a points system), with each study giving a slightly different result.
A meta-analysis of the included studies (data not included in this paper) indicated that overall, around 14 per cent of people adhered to the healthiest lifestyle, whereas 11 per cent adhered to the unhealthiest lifestyle, although the range in both categories was large across all the studies (from four per cent to 42 per cent for the healthiest lifestyle and from 3 per cent to 43 per cent for the unhealthiest lifestyle) . It is clear from the results, said the authors, there are clearly large rooms for improvement in lifestyle across all countries.
Although bodyweight plays a dominant role in the risk of type 2 diabetes, its individual association with the condition was found to be weaker than that of combined lifestyle factors; furthermore, lifestyle behaviours such as physical activity, diet quality and sleep pattern, have been shown to affect bodyweight. Within this new research, several studies reported that each additional lifestyle factor was associated with an 11-61 per cent lower risk of type 2 diabetes.
This study also considered the potential benefits of a healthy lifestyle on the management of type 2 diabetes – an important clinical issue. Compared with diabetic individuals with the least healthy lifestyle, those with the healthiest lifestyle displayed a 56 per cent lower risk of all-cause mortality, a 49 per cent lower risk of CVD mortality and a 31 per cent lower risk of cancer mortality, as well as a 52 per cent lower risk of developing CVD.
As most studies were conducted in high-income countries and most participants were of white ethnicity, evidence from other populations is needed. Also, as type 2 diabetes is now increasingly seen in adolescents and young adults, the authors recommend more research on the associations of healthy lifestyle with diabetes and diabetes complications in these age groups.