From the Journals

Even an hour’s walk a week lowers risk in type 2 diabetes



Performing any level of leisure-time physical activity reduces the risk for neuropathy and nephropathy in individuals with type 2 diabetes, by between one-fifth and one third, although the impact on retinopathy is weaker, reveals a cohort study of U.K. individuals.

The research, based on data from more than 18,000 participants in the U.K. Biobank, suggests that the minimal level of self-reported activity to reduce the risk for both neuropathy and nephropathy may be the equivalent of less than 1.5 hours of walking per week.

The results are “encouraging and reassuring for both physicians and patients,” lead author Frederik P.B. Kristensen, MSc, PhD student, department of clinical epidemiology, Aarhus (Denmark) University, said in an interview.

Couple walking for exercise Ariel Skelley/Getty Images

“Our findings are particularly promising for neuropathy since, currently, no disease-modifying treatment exists, and there are limited preventive strategies available.”

Mr. Kristensen highlighted that “most diabetes research has focused on all-cause mortality and macrovascular complications. In the current study, we also found the same pattern for microvascular complications: Even small amounts of physical activity will benefit your health status.”

The minimal level of activity they identified, he said, is also an “achievable [goal] for most type 2 diabetes patients.”

Mr. Kristensen added, however, that the study was limited by excluding individuals with limited mobility and those living in temporary accommodation or care homes.

And prospective studies are required to determine the dose-response relationship between total, not just leisure-time, activity – ideally measured objectively – and risk for microvascular complications, he observed.

The research was published recently in Diabetes Care.

Impact of exercise on microvascular complications in T2D has been uncertain

The authors point out that microvascular complications – such as nerve damage (neuropathy), kidney problems (nephropathy), and eye complications (retinopathy) – occur in more than 50% of individuals with type 2 diabetes and have a “substantial impact” on quality of life, on top of the impact of macrovascular complications (such as cardiovascular disease), disability, and mortality.

Although physical activity is seen as a “cornerstone in the multifactorial management of type 2 diabetes because of its beneficial effects on metabolic risk factors,” the impact on microvascular complications is “uncertain” and the evidence is limited and “conflicting.”

The researchers therefore sought to examine the dose-response association, including the minimal effective level, between leisure-time physical activity and neuropathy, nephropathy, and retinopathy.

They conducted a cohort study of individuals aged 37-82 years from the U.K. Biobank who had type 2 diabetes, which was identified using the Eastwood algorithm and/or an A1c greater than or equal to 48 mmol/mol (6.5%).

Individuals with type 1 diabetes or gestational diabetes were excluded, as were those with major disabling somatic disorders, neurodegenerative diseases, and mental disorders, among others.

Leisure-time physical activity was based on the self-reported frequency, duration, and types of physical activities and was combined to calculate the total leisure time activity in MET-hours per week.

Using the American Diabetes Association/World Health Organization recommendations of 150-300 minutes of moderate to vigorous leisure-time physical activity per week, the researchers determined the recommended moderate activity level to be 150 minutes, (equivalent to 2.5 hours, or 7.5 MET-hours per week).

In all, 18,092 individuals with type 2 diabetes were included in the analysis, of whom 37% were women. The mean age was 60 years.

Ten percent of participants performed no leisure-time physical activity, 38% performed activity below the threshold for moderate activity, 20% performed at the recommended level, and 32% were more active.

Those performing no physical activity were more likely to be women, to be younger, to have a higher body mass index, and to have a greater average A1c, as well as have a more unfavorable sociodemographic and behavioral profile.

Over a median follow-up of 12.1 years, 3.7% of the participants were diagnosed with neuropathy, 10.2% with nephropathy, and 11.7% with retinopathy, equating to an incidence per 1,000 person-years of 3.5, 9,8, and 11.4, respectively.

The researchers found that any level of physical activity was associated with an approximate reduction in the risk for neuropathy and nephropathy.

Multivariate analysis indicated that, compared with no physical activity, activity below the recommended level was associated with an adjusted hazard ratio (aHR) for neuropathy of 0.71, whereas the aHR for activity at the recommended level was 0.73 and that for activity above the recommended level was 0.67.

The aHR for nephropathy, compared with no physical activity, was 0.79 for activity below the recommended level, 0.80 for activity at the recommended level, and 0.80 for activity above the recommended level.

The association between physical activity and retinopathy was weaker, however, at aHRs of 0.91, 0.91, and 0.98 for activity below, at, and above the recommended level, respectively.

The researchers suggest that this lower association could be due to differences in the etiology of the different forms of microvascular complications.

Hyperglycemia is the key driver in the development of retinopathy, they note, whereas other metabolic risk factors, such as obesity, insulin resistance, inflammation, dyslipidemia, and hypertension, play a role in neuropathy and nephropathy.

The associations were also less pronounced in women.

Mr. Kristensen said that this is “an important area that needs to be addressed.”

“While different rates between men and women regarding incidence of type 2 diabetes, metabolic risk factors, complications, and the initiation of, and adherence to, therapy have been found,” he continued, “the exact mechanisms remain unclear. We need a further understanding of sex-differences in metabolic regulation, as well as in material living conditions, social and psychological factors, and access to health care, which may influence the risk of complications.”

Mr. Kristensen added, “Sex differences may be present in more areas than we are aware.”

Mr. Kristensen is supported by a PhD grant from Aarhus University. Other authors received funding from the Danish Diabetes Association, the Australian National Health and Medical Research Council, the New South Wales Government, the Spanish Ministry of Universities, the European Union NextGenerationEU/PRTR (Plan de Recuperación) through a Margarita Salas contract of the University of Vigo, and the Government of Andalusia, Research Talent Recruitment Programme. No relevant financial relationships were declared.

A version of this article appeared on

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