Lisa Chasan-Taber

Exercise and Type 2 Diabetes The American College of Sports Medicine and the American Diabetes Association: joint position statement

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes, many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay type 2 diabetes, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower type 2 diabetes risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes mellitus, and safe and effective practices for PA with diabetes-related complications.

Exercise and Type 2 Diabetes: The American College of Sports Medicine and the American Diabetes Association: Joint Position Statement Executive Summary

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes, many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay type 2 diabetes, along with positively impacting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower risk of type 2 diabetes by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. …

Exercise and type 2 diabetes: American College of Sports Medicine and the American Diabetes Association: joint position statement. Exercise and type 2 diabetes.

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes mellitus (T2DM), many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay T2DM, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower T2DM risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes, and safe and effective practices for PA with diabetes-related complications.

Development and Validation of a Pregnancy Physical Activity Questionnaire

PURPOSE The effect of physical activity during pregnancy on maternal and fetal health remains controversial and studies have yet to identify the optimal dose of physical activity associated with favorable pregnancy outcomes. The aim of this study was to develop and validate a pregnancy physical activity questionnaire (PPAQ). METHODS To ascertain the type, duration, and frequency of physical activities performed by pregnant women, three 24-h physical activity recalls were administered to 235 ethnically diverse prenatal care patients at a large tertiary care facility in western Massachusetts. The relative contribution of each activity to between-person variance in energy expenditure was used to establish the list of activities for the PPAQ. The PPAQ is self-administered and asks respondents to report the time spent participating in 32 activities including household/caregiving, occupational, sports/exercise, transportation, and inactivity. To validate the PPAQ, 54 pregnant women completed the PPAQ and then wore a Manufacturing Technology, Inc. actigraph for the following 7 d. At the end of the 7-d period, the PPAQ was repeated. RESULTS Intraclass correlation coefficients used to measure reproducibility of the PPAQ were 0.78 for total activity, 0.82 for moderate activity, 0.81 for vigorous activity, and ranged from 0.83 for sports/exercise to 0.93 for occupational activity. Spearman correlations between the PPAQ and three published cut points used to classify actigraph data ranged from 0.08 to 0.43 for total activity, 0.25 to 0.34 for vigorous activity, 0.20 to 0.49 for moderate activity, and -0.08 to 0.22 for light-intensity activity. Correlations were higher for sports/exercise and occupational activities as compared to household/caregiving activities. CONCLUSIONS household/caregiving activities. CONCLUSIONS The PPAQ is a reliable instrument of physical activities during pregnancy.

Prospective Study of Oral Contraceptives and Hypertension Among Women in the United States

BACKGROUND Oral contraceptives induce hypertension in approximately 5% of users of high-dose pills that contain at least 50 micrograms estrogen and 1 to 4 mg progestin, and small increases in blood pressure have been reported even among users of modern low-dose formulations. However, neither the responsible hormone in the oral contraceptive nor particular subgroups of women who might be susceptible to the hypertensive effect of oral contraceptives have been identified. METHODS AND RESULTS In a prospective cohort study in the United States, 68 297 female nurses aged 25 to 42 years and free of diagnosed hypertension, diabetes, coronary heart disease, stroke, and cancer at baseline were followed up for 4 years. During 231 006 person-years of follow-up, 1567 incident cases of hypertension were diagnosed. Compared with women who had never used oral contraceptives, the age-adjusted relative risk was 1.5 (95% CI = 1.2 to 1.8) for current use and 1.1 (95% CI = 0.9 to 1.2) for past use. After adjustment for age, body mass index, hormones cigarette smoking, family history of hypertension, parity, physical activity, alcohol intake, and ethnicity, current users of oral contraceptives had an increased risk of development of hypertension (RR = 1.8; 95% CI = 1.5 to 2.3) compared with women who had never used them. The multivariate relative risk for past users was 1.2 (95% CI = 1.0 to 1.4). There were no important modifying effects of age, family history of hypertension, ethnicity, or body mass index. CONCLUSIONS Current users of oral contraceptives had a significant, moderately increased risk of hypertension. However, among this group, only 41.5 cases per 10 000 person-years could be attributed to oral contraceptive use. Risk decreased quickly with cessation of oral contraceptives, and past users appeared to have only a slightly increased risk.

Postpartum diabetes screening in women with a history of gestational diabetes.

OBJECTIVE: Women with a history of gestational diabetes mellitus (GDM) are at high risk for developing type 2 diabetes (diabetes mellitus, DM). The American Diabetes Association recommends regular postpartum diabetes screening for women with a history of GDM, but the American College of Obstetricians and Gynecologists (ACOG) is not as directive. We sought to examine postpartum glycemic testing in women diagnosed with GDM. METHODS: We conducted an observational cohort study of women diagnosed with GDM at one of two large academic medical centers between 2000 and 2001. Kaplan-Meier estimates of the time from delivery to the first postpartum DM screening tests were determined, and predictors of postpartum DM screening were examined using Cox proportional hazards testing. RESULTS: Only 37% of eligible women underwent the postpartum diabetes screening tests recommended by the American Diabetes Association (fasting glucose or oral glucose tolerance test [OGTT]), with a median time from delivery to the first such testing of 428 days. By comparison, 94% of women underwent postpartum cervical cancer screening using a Papanicolaou (Pap) test, with a median time from delivery to Pap testing of 49 days. Even when random glucose testing was included in a broad definition of postpartum DM screening (random or fasting glucose, glycosylated hemoglobin, or OGTT), only two thirds of women (67%) received a postpartum glycemic assessment. CONCLUSION: In the population studied, only 37% of women with a history of GDM were screened for postpartum DM according to guidelines published by the American Diabetes Association. Efforts to improve postpartum DM screening in this high-risk group are warranted. LEVEL OF EVIDENCE: II-2

Exercise and diabetes.

As rates of diabetes mellitus and obesity continue to increase, physical activity continues to be a fundamental form of therapy. Exercise influences several aspects of diabetes, including blood glucose concentrations, insulin action and cardiovascular risk factors. Blood glucose concentrations reflect the balance between skeletal muscle uptake and ambient concentrations of both insulin and counterinsulin hormones. Difficulties in predicting the relative impact of these factors can result in either hypoglycemia or hyperglycemia. Despite the variable impact of exercise on blood glucose, exercise consistently improves insulin action and several cardiovascular risk factors. Beyond the acute impact of physical activity, long-term exercise behaviors have been repeatedly associated with decreased rates of type 2 diabetes. While exercise produces many benefits, it is not without risks for patients with diabetes mellitus. In addition to hyperglycemia, from increased hepatic glucose production, insufficient insulin levels can foster ketogenesis from excess concentrations of fatty acids. At the opposite end of the glucose spectrum, hypoglycemia can result from excess glucose uptake due to either increased insulin concentrations, enhanced insulin action or impaired carbohydrate absorption. To decrease the risk for hypoglycemia, insulin doses should be reduced prior to exercise, although some insulin is typically still needed. Although precise risks of exercise on existing diabetic complications have not been well studied, it seems prudent to consider the potential to worsen nephropathy or retinopathy, or to precipitate musculoskeletal injuries. There is more substantive evidence that autonomic neuropathy may predispose patients to arrhythmias. Of clear concern, increased physical activity can precipitate a cardiac event in those with underlying CAD. Recognizing these risks can prompt actions to minimize their impact. Positive actions that are part of exercise programs for diabetic patients emphasize SMBG, foot care and cardiovascular functional assessment. SMBG provides critical information on the impact of exercise and is recommended for all patients before, during and after exercise. More frequent monitoring (and for longer periods following exercise) is recommended for those with hypoglycemia unawareness or those performing high-intensity exercise. Preventing the sequelae of an exercise-induced severe hypoglycemic reaction can be as simple as carrying glucose tablets or gel, a diabetic identification bracelet or card, or exercising with an individual who is aware of the circumstances. In addition to blood glucose concentrations, proper foot care is critical to people with diabetes who exercise and includes considering type of shoe, type of exercise, inspection of skin surfaces and appropriate evaluation and treatment of lesions (calluses and others). Those with severe neuropathy can consider alternatives to weight-bearing exercises. Precipitation of clinical CAD is of great concern for all diabetic patients participating in exercise activities. Although a sufficiently sensitive and specific screening test for coronary disease has not been identified, those planning an exercise program of moderate intensity or greater should be evaluated. Initial cardiac assessment should include exercise testing as well as identifying risk for autonomic neuropathy. In addition to noting maximal heart rate and blood pressure as well as ischemic changes, exercise tolerance testing can identify anginal thresholds and patients with asymptomatic ischemia. Those without symptoms should be counseled regarding target pulse rates to avoid inducing ischemia. Ischemic changes need to be evaluated for either further diagnostic testing or pharmacological intervention. For patients with diabetes mellitus, the overall benefits of exercise are clearly significant. Clinicians and patients must work together to maximize these benefits while minimizing risks for negative consequences. Identifying and preventing potential problems beforehand can reduce adverse outcomes and promote this important approach to healthy living.

Predictors of excessive and inadequate gestational weight gain in Hispanic women.

Factors influencing gestational weight gain are incompletely understood, particularly among Hispanic women. We assessed medical, sociodemographic, behavioral, and psychosocial predictors of overall gestational weight gain, as well as gains below, within, or above the range recommended by the Institute of Medicine (IOM) within a prospective study of 770 Hispanic (predominantly Puerto Rican) prenatal care patients at a large tertiary care facility in Western Massachusetts. One third of women gained within the recommended range, 22% gained below, and 45% gained above the range. In multivariate analysis, women in the highest category of BMI (Ptrend < 0.001) and parity (Ptrend < 0.001) gained on average 9 lbs less than those in the lowest category. Increasing time in residence in the continental United States (Ptrend < 0.01) as well as a number of prenatal care visits (Ptrend = 0.03) were positively associated with weight gain. Overweight women (odds ratio (OR) = 2.2, 95% confidence interval (CI) 1.3, 3.8) and those over age 30 years (OR = 2.5, 95% CI 1.2, 5.0) were more likely to gain above the IOM range as compared to normal‐weight women and those aged 20–24, respectively. Women with <10 years of residence in the United States were 50% less likely to gain above the IOM range as compared to third‐generation women (95% CI 0.3, 0.9). Findings identify determinants of gestational weight gain which can form the basis of targeted interventions in this rapidly growing ethnic group.

Correlates of physical activity in pregnancy among Latina women

Objectives: National data indicate that Latina women are less active than non-Latina white women and are at higher risk of gestational diabetes and subsequent type 2 diabetes. Physical activity may reduce risk of maternal disorders of pregnancy, but sparse data exists on the correlates of physical activity in pregnant Latina women. Methods: We conducted a prospective cohort study from 2000 to 2004 among healthy Latina prenatal care patients in a public clinic and midwifery practice. Physical activity was assessed using a modified version of the Kaiser Physical Activity Survey (KPAS) in early and mid pregnancy. Results: A total of 1,231 women (predominantly of Puerto Rican heritage) met the eligibility criteria and were enrolled. Participation in household/caregiving, occupational, sports/exercise, and active living decreased from prepregnancy to pregnancy. Overall, women who were more active prior to pregnancy were more likely to have high levels of participation in every domain of pregnancy activity. Women with the highest level of participation in occupational activity during pregnancy (defined as the highest quartile of activity, compared with the lower three quartiles) were more likely to be older, college-educated, have higher income, and have fewer children. Women with the highest level of household/caregiving activity were more likely to be older, have more children, be U.S. born, and prefer Spanish while women with the highest levels of sports/exercise during pregnancy were less likely to prefer Spanish. Conclusions: These findings suggest that sociodemographic, acculturation, health, and behavioral correlates of physical activity vary by domain among Latina women. Programs aimed at promoting physical activity during pregnancy in this high risk ethnic group should recognize these differences.

Epidemiology of Oral Contraceptives and Cardiovascular Disease

Early epidemiologic studies of combined oral contraceptives containing high doses of estrogen (high-dose oral contraceptives) found that these drugs increased risk for cardiovascular disease, but formulations of oral contraceptives have changed dramatically over the past 30 years. Modern oral contraceptives have one fourth of the estrogen and one tenth of the progestogen found in the original combinations. Initially, oral contraceptives included at least 50 g of ethinylestradiol or mestranol and a progestogen, typically norethindrone. Because estrogen was suspected of increasing risk for thromboemboli, contraceptives that contained less than 50 g of estrogen and a new progestogen, levonorgestrel, were introduced. More recently, the newest progestogens (desogestrel, gestodene, and norgestimate) in combination with no more than 35 g of ethinylestradiol have become available. Because the new progestogens have fewer androgenic metabolic effects and do not adversely affect lipid levels, they may be associated with lower risk for cardiovascular disease. As a result of these marked changes in formulation, the findings of early epidemiologic studies may not be fully generalizable to todays preparations. The population using oral contraceptives has also changed. Women begin use at younger ages and continue for longer periods. Although serious cardiovascular disease is uncommon among women in their 20s and 30s, it is not rare in older premenopausal women, especially smokers. We review epidemiologic studies of myocardial infarction, stroke, and thromboembolic disease in relation to oral contraceptives, especially those that contain less than 50 g of estrogen. Methods We searched the MEDLINE database for all English-language epidemiologic studies of oral contraceptives and cardiovascular disease published between 1967, when contraceptives containing low doses of estrogen (low-dose oral contraceptives) were introduced in the United States, and June 1997. Animal and metabolic studies were reviewed only if they were relevant to the mechanism of action of oral contraceptives. We also searched textbooks, meeting proceedings, and reference lists from identified articles. We did not consider abstracts because these typically present preliminary data and provide insufficient detail. We retrieved 374 relevant studies. Those without a quantitative estimate of effect were excluded, as were those that did not satisfy the following date and dose criteria. By 1976, low-dose contraceptives dominated the U.S. market. In 1988, 82% of prescriptions for oral contraceptives were formulations that contained less than 50 g of estrogen [1]. Contraceptives that contained more than 50 g of estrogen were withdrawn in the United States in 1989 and in the United Kingdom in 1984 [2]. We included studies published since low-dose contraceptives were introduced in the United States in 1967 (they were introduced in the United Kingdom in 1973). For studies that did not specify the dose of estrogen used, we inferred that after 1988 (in the United States) and 1984 (in the United Kingdom), the study population predominantly used low-dose contraceptives. Formulations that contain 50 g of mestranol, a less potent type of estrogen, were not considered to be high-dose oral contraceptives because they are equivalent to formulations that contain 35 g of ethinylestradiol. Data were organized by cardiovascular end point, study design, estrogen dose, and type of progestogen. Data on relative and absolute risk are presented to address current prescription guidelines. Relative risks are useful for etiologic study but provide little guidance in clinical or public health settings. When the baseline risk for disease is low, the absolute excess risk may be small even if the relative risk is high. Data Synthesis Myocardial Infarction Current Use The current use of oral contraceptives increases risk for myocardial infarction, but most of the excess risk is attributable to an interaction with cigarette smoking. For women who smoked 25 or more cigarettes per day and used oral contraceptives compared with women who did neither, Shapiro and colleagues [3] reported a relative risk of 39 and Rosenberg and coworkers [4] found a relative risk of 30. These extreme relative risks contrast with the four- to eightfold excess risks associated with smoking and the far lower risks seen in oral contraceptive users who do not smoke. Hence, studies of oral contraceptives and risk for myocardial infarction that do not evaluate smokers and nonsmokers separately are of limited use. Even those that adjust for smoking may not yield reliable estimates because of the interaction. Taken together, casecontrol and cohort studies suggest that current users of oral contraceptives who are younger than 40 years of age and do not smoke have little or no increase in risk for myocardial infarction. Table 1 shows data from studies done since 1967 in nonsmokers [3, 5-12]. The more recent studies tend to find even smaller relative risks for current oral contraceptive use (regardless of smoking) than the earlier studies. Table 2 shows data from studies of low-dose contraceptives published since 1967 that did not stratify by smoking [13-23]. Among cohort studies, the results were as follows: No cases were seen in the Group Health Cooperative study [20, 24], a relative risk of 0.2 (95% CI, 0.05 to 0.7) was seen in the Finnish study by Hirvonen and Idanpaan-Heikkila [21], and a relative risk of 1.1 (CI, 0.5 to 2.5) was seen in the Copenhagen City Heart Study [19]. Table 1. Relative Risk for Myocardial Infarction in Current Users of Oral Contraceptives Who Do Not Smoke, with Nonusers as Referent* Table 2. Relative Risk for Myocardial Infarction in Current Users of Low-Dose Oral Contraceptives, with Nonusers as Referent* Most studies have been too small to address whether the risk for myocardial infarction from oral contraceptives differs according to coronary risk factors other than smoking. A recent hospital-based casecontrol study [18] found significantly increased risks for myocardial infarction in users of low-dose contraceptives in Europe and developing countries (4.69 and 2.93, respectively). These relative risks were higher than those seen in most previous studies, and the authors suggest that coexistent risk factors and inadequate screening among contraceptive users were responsible for the differences. In nonsmoking women who reported having their blood pressure checked before the current episode of contraceptive use, relative risks (1.34 [CI, 0.34 to 5.34] in Europe and 2.66 [CI, 0.81 to 8.79] in developing countries) were not statistically significant. The possibility of a synergistic effect between high blood pressure and oral contraceptive use has been suggested [11, 15]. The use of oral contraceptives is concentrated among young, fertile women with low incidence of myocardial infarction. In the United States, the baseline risk for fatal ischemic heart disease ranges from 1 to 2 per 100 000 persons in women younger than 35 years of age to 4.1 per 100 000 persons in women 35 to 39 years of age and to 10 to 21 per 100 000 persons for women in their 40s [25]. The bulk of the evidence suggests that nonsmokers have little or no increase in risk. New Progestogens Oral contraceptives that contain the new progestogens may not carry the same risk as earlier formulations, but their effect on the incidence of myocardial infarction or stroke has not been fully examined. A recent review [26] concluded that contraceptives containing desogestrel and gestodene have fewer adverse effects on carbohydrate and lipoprotein metabolism. Case-control studies of oral contraceptives that contain the newest progestogens suggest that these preparations carry lower relative risks for myocardial infarction than earlier preparations, but the data are sparse and based on fewer than 10 exposed cases [18, 22, 23] (Table 2 and Table 3). Moreover, because the data in these studies were not stratified by smoking status, the findings are difficult to interpret. The results suggest that the newer oral contraceptive preparations have an interaction with cigarette smoking but that the combined effect may be attenuated compared with that seen with earlier preparations. Table 3. Relative Risk for Myocardial Infarction by Type of New Progestogen, with Nonusers as Referent Past Use Because oral contraceptives can adversely affect coronary risk factors, there is considerable concern that women in their 50s and 60s would have delayed effects from the use of oral contraceptives. The data consistently show that past use is not associated with increased risk. In a meta-analysis of 13 studies of past use of oral contraceptives and risk for myocardial infarction [3, 5-711-13, 27-32], Stampfer and coworkers [33] estimated that past users had a pooled relative risk of 1.01 (CI, 0.91 to 1.13). These findings suggest that any increase in risk for myocardial infarction due to oral contraceptive use occurs only with current use and probably acts through an acute prothrombotic interaction with cigarette smoking. Angiographic studies of young women with myocardial infarction tend to show an absence of atherosclerosis in cases associated with current or recent use of oral contraceptives [34-36]. In monkeys who were fed an atherogenic diet, oral contraceptives markedly decreased the extent of atherosclerosis compared with placebo [37, 38]. Stroke Studies of oral contraceptives and stroke are often small, typically do not discriminate between hemorrhagic and thromboembolic stroke, and often do not control for major risk factors for stroke [39-41]. Unlike early studies, most recent prospective studies have not shown an increased risk for stroke among either past users of oral contraceptives or persons who had ever used oral contraceptives [20, 28, 42, 43]. Studies of stroke in current users have yielded inconsistent results. Table 4 shows data from studies of strok