Can being physically inactive raise my risk of developing type 2 diabetes?

According to the Annals of Internal Medicine clinical practice guidelines, the following factors increase the risk of developing type 2 diabetes mellitus (T2DM): ¹

• Aged 45 years or older. 
• First-degree relative with type 2 diabetes
• Certain racial and ethnic groups including African, Hispanic, Asian, Pacific Islander, or Native American 
• History of gestational diabetes 
• Delivery of an infant weighing nine pounds or more
• Polycystic ovary syndrome 
• Being overweight, especially abdominal obesity 
• Cardiovascular disease 
• Hypertension 
• Dyslipidemia, including low HDL cholesterol, high LDL cholesterol, and high triglycerides.
• Other features of metabolic syndrome

The American Diabetes Association (ADA) lists the following additional recommended criteria for diabetes testing in asymptomatic adults: ² 

• Physical inactivity 
• Other conditions associated with insulin resistance.
• Prediabetes
• Certain medications including some HIV medications, glucocorticoids, thiazide diuretics, and atypical antipsychotics.
• HIV

Physical Inactivity

While the amount of time a person is sedentary can raise the risk of developing T2DM, it is one of the less predictive factors. One study seeking to make a new assessment tool found that the following risk factors are most predictive of the development of T2DM, in order of most predictive to least predictive:³  

• Aged 60 years or older. 
• Extreme Obesity  
• Aged 50-59 years.
• Obesity 
• Aged 40-49 years. 
• Male 
• Family history of diabetes 
• History of hypertension 
• Overweight 
• Physical Inactivity

A retrospective study of the Danish Health Examination Survey (DANHES) data (n=72,608) found that the total number of hours sitting each day had minimal effect on the overall risk of developing T2DM.⁴ For those that sat 6-10 hours daily, the incidence of T2DM was 2.4% (5.0 events per 1,000 person-years) as opposed to 2.7% for those that sat over 10 hours (5.5 events per 1,000 person-years). When adjusted for other risk factors and level of physical activity, the hazard ratios were 1.07 (95% CI [0.96-1.20]) and 1.11 (95% CI [0.95-1.28]) respectively when compared to those who sat for less than six hours daily.

One analysis of the data collected in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study (n=23,855) found that the incidence of T2DM increased with more time spent sedentary specifically measured as self-reported time spent watching television (TV).⁵ Among those who watched <1 hour of TV per day, there was a 2.0% incidence of developing T2DM (unadjusted rate of 20.3 events per 1,000 person-years). For each subsequent hour spent watching TV per day, incidence increased: 2.9% for those who watched 1-2 hours of TV (29.3 per 1,000 person-years), 3.6% for 2-3 hours (36.3 per 1,000 person-years), 6.0% for 3-4 hours (59.9 per 1,000 person-years), and 6.8% for >4 hours (67.7 per 1,000 person-years).

However, physical activity can decrease the risk of developing T2DM. An Australian cohort study (n=60,404) examining the relationship between T2DM and a variety of risk factors found that hours sitting per day was not a predictor of the development of T2DM (1.5% incidence for both those sitting <8 hours per day and those sitting ≥11 hours).⁶ However, total minutes of moderate to vigorous activity had a significant effect on risk (1.4% incidence of T2DM development for those exercising ≥300 minutes per week vs 2.2% for those exercising <150 minutes).

Another study that examined the efficacy of statistical models assessing the risk of T2DM found that there was a high correlation between the level of physical activity and diabetes diagnosis, with the average duration of daily moderate to vigorous exercise estimated to be 47 minutes shorter amongst participants with diabetes than those without diabetes (61 minutes per day vs 108 minutes per day).⁷

Risk Reduction

The amount of time a person spends inactive each week contributes less to the overall risk of developing T2DM than the amount of time spent performing moderate to vigorous physical activity each week.

Both the Annals of Internal Medicine and ADA clinical practice guidelines recommend the following to prevent or delay the development of type 2 diabetes:^1,8 

• Adults who are overweight or obese should lose and maintain a loss of at least 7% of their initial body weight. 
• At least 150 minutes per week of moderate-intensity physical activity, like brisk walking 
• Eat a healthy diet with the goal of weight loss and reduction of total caloric intake.

These lifestyle modifications have been found to prevent or delay T2DM in even high-risk populations. The Diabetes Prevention Program Outcomes Study (DPPOS) found that weight loss was the most important factor in reducing the risk of developing T2DM.^9,10 Secondary was performing at least 150 minutes of physical activity per week, even without achieving the weight loss goal.

References

1. Vijan S. Type 2 diabetes. Annals of internal medicine. Nov 5 2019;171(9):Itc65-itc80. doi:10.7326/aitc201911050
2. 2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2022. Diabetes Care. Jan 1 2022;45(Suppl 1):S17-s38. doi:10.2337/dc22-S002
3. Bang H, Edwards AM, Bomback AS, et al. Development and validation of a patient self-assessment score for diabetes risk. Annals of internal medicine. Dec 1 2009;151(11):775-83. doi:10.7326/0003-4819-151-11-200912010-00005
4. Petersen CB, Bauman A, Tolstrup JS. Total sitting time and the risk of incident diabetes in Danish adults (the DANHES cohort) over 5 years: a prospective study. Br J Sports Med. Nov 2016;50(22):1382-1387. doi:10.1136/bjsports-2015-095648
5. Ford ES, Schulze MB, Kröger J, Pischon T, Bergmann MM, Boeing H. Television watching and incident diabetes: Findings from the European Prospective Investigation into Cancer and Nutrition-Potsdam Study. J Diabetes. Mar 2010;2(1):23-7. doi:10.1111/j.1753-0407.2009.00047.x
6. Ding D, Chong S, Jalaludin B, Comino E, Bauman AE. Risk factors of incident type 2-diabetes mellitus over a 3-year follow-up: Results from a large Australian sample. Diabetes Res Clin Pract. May 2015;108(2):306-15. doi:10.1016/j.diabres.2015.02.002
7. Turi KN, Buchner DM, Grigsby-Toussaint DS. Predicting Risk of Type 2 Diabetes by Using Data on Easy-to-Measure Risk Factors. Prev Chronic Dis. Mar 9 2017;14:E23. doi:10.5888/pcd14.160244
8. 3. Prevention or Delay of Type 2 Diabetes and Associated Comorbidities: Standards of Medical Care in Diabetes-2022. Diabetes Care. Jan 1 2022;45(Suppl 1):S39-s45. doi:10.2337/dc22-S003
9. The Diabetes Prevention Program (DPP): description of lifestyle intervention. Diabetes Care. Dec 2002;25(12):2165-71. doi:10.2337/diacare.25.12.2165
10. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. Lancet Diabetes Endocrinol. Nov 2015;3(11):866-75. doi:10.1016/s2213-8587(15)00291-0