Physical Activity, Metabolic Factors, and the Incidence of Coronary Heart Disease and Type 2 Diabetes

Abstract

Objective: To examine the role of nonfasting serum insulin level and components of the insulin resistance syndrome in the relationship between physical activity and the incidence of coronary heart disease and type 2 diabetes.Methods: Prospective study of 5159 men aged 40 to 59 years with no history of coronary heart disease, type 2 diabetes, or stroke drawn from general practices in 18 British towns. During an average follow-up period of 16.8 years, there were 616 cases of major coronary heart disease events (fatal and nonfatal) and 196 incident cases of type 2 diabetes.Results: After adjustment for potential confounders (lifestyle characteristics and preexisting disease), physical activity was inversely related to coronary heart disease rates, with the lowest rates in the men undertaking moderate physical activity and with no further benefit thereafter. For type 2 diabetes, risk decreased progressively with increasing levels of physical activity. Physical activity was associated with serum insulin level and with factors associated with insulin, ie, heart rate, hyperuricemia, diastolic blood pressure, and high-density lipoprotein cholesterol level, and with ␥-glutamyltransferase level, a possible marker of hepatic insulin resistance. Adjustment for insulin and associated factors made little difference to the relationship between physical activity and risk of coronary heart disease. By contrast, these factors together with ␥-glutamyltransferase level appear to explain a large proportion of the reduction in risk of type 2 diabetes associated with physical activity. Conclusions:The relationship between physical activity and type 2 diabetes appears to be mediated by serum true insulin level and components of the insulin resistance syndrome. However, these factors do not appear to explain the inverse relationship between physical activity and coronary heart disease.

Leisure time physical activity and the risk of type 2 diabetes in men and women from the general population

“…Although in the present study leisure time physical activity among obese and nonobese men was not intensive enough to significantly reduce the risk of type 2 diabetes, it could nevertheless have a positive effect on cardiovascular risk factors and on the various components of the metabolic syndrome. This assumption is confirmed by Wannamethee et al [25], who reported that the relationship between physical activity and type 2 diabetes appears to be mediated by serum true insulin level and components of the insulin resistance syndrome. Furthermore, the Insulin Resistance Atherosclerosis Study demonstrated a positive association between both vigorous and nonvigorous physical activity and insulin sensitivity in a cross-sectional study of 1,467 men and women [30].…”

“…Further results from the Nurses Health Study suggested that, independently of exercise levels, sedentary behaviours, especially TV watching, were associated with significantly elevated risk of type 2 diabetes and obesity, whereas even light to moderate activities were associated with a substantially lower risk [24]. Also, an inverse association between exercise and incidence of type 2 diabetes was observed among residents of the UK [21,25] and Finland [13,26]. The findings in the present study extend the literature showing that leisure time physical activity is associated with a reduction in risk of type 2 diabetes.…”

Low-intensity physical activity is associated with reduced risk of incident type 2 diabetes in older adults: evidence from the English Longitudinal Study of Ageing

“…Previous studies have shown that physical activity remained significantly related to incident diabetes after adjustment for a single measure of SES (typically education [16][17][18] but also occupational class [19]). Our study has accounted in a fuller way for SES by adjusting models for both education and total wealth, which is one of the best measures of SES for older people [20], and thus has more convincingly shown that the significant association between physical activity and incident diabetes is not an artefact of residual confounding because of inadequate adjustment for SES.…”

Low muscle mass in older men: The role of lifestyle, diet and cardiovascular risk factors

“…cigarette smoking, physical activity, alcohol intake and social class were self-reported via questionnaire and blood lipids and blood pressure were measured at the physical examination as described elsewhere (3,13,24). Men were classified into four smoking groups (never; long-term ex; recent ex; current).…”