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Results for “Glycemic variability”

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At least 109 records · Page 6Linked to original sources

PubMed2005

Modulation of food intake by glucose in patients with type 2 diabetes.

OBJECTIVE: A gain in body weight is a common adverse effect of glucose-lowering therapies in patients with type 2 diabetes, the mechanisms of which are not completely understood. Blood glucose is considered to play a crucial role in the regulation of food intake. On this background, we hypothesized that a short-term reduction of blood glucose concentration to normal values acutely increases food intake in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: To test this hypothesis, 12 patients with type 2 diabetes were examined twice, once during a euglycemic (5.0 mmol/l) clamp experiment and another time during a hyperglycemic (10.5 mmol/l) clamp. The experiments were performed in a single-blind fashion with the order of conditions balanced across patients. On both clamp conditions, insulin was infused at a constant rate of 2.5 mU/kg per min for 125 min. Simultaneously, a glucose solution was infused at a variable rate to achieve target glycemic levels. During the final 30 min of the clamps, the patients were allowed to eat as much as they liked from a standard breakfast buffet. RESULTS: Compared with the hyperglycemic condition, the patients ingested on average 25 +/- 10% more energy during euglycemia (645 +/- 75 vs. 483 +/- 37 kcal; P = 0.029). The increased energy intake during euglycemia was equally distributed across macronutrient components, i.e., during euglycemia the patients ate more carbohydrates (+27.1 +/- 11.4%; P = 0.037), fat (+22.5 +/- 10.0%; P = 0.046), and proteins (+25.2 +/- 11.2%; P = 0.046) than during hyperglycemia. Circulating levels of insulin, amylin, leptin, ghrelin, and glucagon-like peptide-1 did not differ between the euglycemic and hyperglycemia clamp, excluding a major contribution of these hormones to the difference in food intake. Summing up the glucose administered intravenously and the food ingested yielded a remarkably similar total energy influx in both conditions (794 +/- 64 vs. 790 +/- 53 kcal; P = 0.961). CONCLUSIONS: Together our data suggest that total energy supply to the organism is tightly regulated on a short-term basis independent of the route of influx. Alternatively, it can be hypothesized that euglycemia stimulated or that hyperglycemia suppressed food intake at the subsequent buffet meal in our type 2 diabetic patients. Regardless of these different interpretations, our data indicate an important regulatory role of glucose for food intake in type 2 diabetic patients that is of considerable clinical relevance.

Blood Glucose↗

PubMed1990

Psychosocial correlates of hemoglobin Alc in young adults with type I diabetes.

To determine whether psychosocial variables are related to long-term glycemic control; trait anxiety, depression, loneliness and life stress were assessed in 48 Type I diabetic patients. Hemoglobin A1c (HbA1c), an indicator of long-term glycemic utilization, was assayed from blood samples drawn shortly before the self-report instruments were administered. Of the psychosocial variables, anxiety was significantly related to current values of HbA1c. The association between anxiety and current HbA1c remained after statistically controlling for potentially confounding variables, including the previous value of HbA1c. Despite the stability of HbA1c values over time, anxiety scores were not significantly correlated with follow-up HbA1c. The implications of the significant relationships between psychological constructs and glycemic control are discussed.

Adolescent↗

PubMed2006

The glycemic index. A current controversy.

The nutrition community is divided over de rol of de Glycemic Index (GI) or Glycemic Load (GL) in the dietetic management of Diabetes Mellitus (DM) and in the prevention of chronic diseases as DM, Obesity, Insulin Resistance (IR), Cardiovascular diseases and Cancer. The concept of GI and GL of food and diet is defined. Methodological problem are analyzed: poor standardization, bad reproducibility and high variability. The factors that determines the food glycemic index and the causes of it variability are analyzed. Recent and qualified clinical and epidemiological evidences about the relation between the GI and GL of food and diet, on the management of DM, and prevention of Obesity, DM, RI, Cardiovascular disease and Cancer, are discussed. Is concluded that there are insufficient evidences of clinical efficacy in the use of this concept for the prevention of Obesity, IR, Cardiovascular diseases and Cancer. In relation to the treatment of DM, ADA states that the most important dietetic tool is the reduction of the total amount of carbohydrates, but accepts that the use of the GI could give additional benefits. Although de GI has the potential to be a valuable clinical tool. For now consumers should focus on eating a diet plant-based, with a variety of vegetables, fruits, whole grain and legumes. At the moment we must be caution in making dietary changes based solely in this concept.

Glycemic Index↗

PubMedDate not supplied

Parental perception and factors associated with glycemic control in pediatric patients with type 1 diabetes.

OBJECTIVE: To compare subjective parental perceptions of short-term diabetes control with objective glycated hemoglobin (HbA1c) measurements in a pediatric population. METHODS: Parents of 159 children and adolescents with type 1 diabetes anonymously completed a questionnaire concerning demographics, parental perception of the child's recent glycemic control, concern about nocturnal blood glucose levels, and factors related to severity of the child's diabetes. Nonparametric correlations were performed among all variables and the child's current HbA1c measurement. Good short-term glycemic control was defined as an HbA1c value of < or = 8.5%. RESULTS: Five factors were found to correlate significantly with good glycemic control, and these variables were subjected to a logistic regression analysis. With use of a cutoff value of 0.58, results explained 26% of the variance and had an overall 71% correct classification rate. Children with good glycemic control were younger, had a shorter duration of diabetes, lived in families with higher socioeconomic status, were less likely to experience hospitalizations due to their diabetes, and had parents who "always worried" about nocturnal blood glucose variations. Parental perception and HbA1c values were not significantly related (P>0.19); 60% of the parents correctly perceived the status of diabetes in their children, and 40% misperceived the level of glycemic control. Further analysis suggested that accuracy of parental perception was highly dependent on the child's level of glycemic control. Parents whose children had lower HbA1c values (< or = 7.5%) correctly perceived the status of blood glucose control in their children, whereas parents whose children had poorer glycemic control (HbA1c > or = 9.5%) had inaccurate perceptions. CONCLUSION: Subjective parental perceptions of diabetes control in their children may not correspond to objective assessments. Our findings suggest a need for more educational feedback concerning HbA1c levels and recommended goals for glycemic control.

Adolescent↗

PubMed1983

Predicting insulin requirements for a portable insulin pump using the Biostator. Evidence for reversible insulin resistance in poorly controlled type I diabetics.

Glycemic control was achieved in 14 patients with insulin-dependent diabetes mellitus (IDDM) by 36-48-h treatment with a recently marketed clinical model, Biostator glucose controller (Life Science Instruments, Miles Laboratories, Elkhart, Indiana). Control was maintained by continuous subcutaneous insulin infusion with a portable pump, programmed using infusion profiles from the Biostator. Control of glycemic excursion with the Biostator was variable among patients. This control, reflected by the M-value or a blood glucose index (mean of pre-, peak, and 2-h postmeal levels for four meals) of each patient, correlated directly with their prior glycemic control, as assessed by hemoglobin A1c (HbA1c) level (r = 0.66, P less than 0.01 and r = 0.82, P less than 0.005, for M-value and blood glucose index, respectively). Total insulin infused by the Biostator/24 h overpredicted the subcutaneous infusion dose required on day 2 of pump treatment (183 +/- 11%, P less 0.001). Therefore, these data were not used to program the portable pump. Instead, total insulin dose was estimated using a dietary glucose/insulin (G/I) ratio. This ratio, derived from dietary total available glucose, urine glucose, and insulin dose/24 h during depot insulin treatment, accurately estimated total insulin for pump infusion (97 +/- 4%). The basal infusion rate of the Biostator between 2400 and 0600 h also exceeded the subcutaneous infusion requirement and was reduced to 40% for the initial pump basal rate. The remainder of the insulin (total minus basal) was distributed as premeal boluses according to the Biostator infusion profile for meals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

Data mining a diabetic data warehouse.

Diabetes is a major health problem in the United States. There is a long history of diabetic registries and databases with systematically collected patient information. We examine one such diabetic data warehouse, showing a method of applying data mining techniques, and some of the data issues, analysis problems, and results. The diabetic data warehouse is from a large integrated health care system in the New Orleans area with 30,383 diabetic patients. Methods for translating a complex relational database with time series and sequencing information to a flat file suitable for data mining are challenging. We discuss two variables in detail, a comorbidity index and the HgbA1c, a measure of glycemic control related to outcomes. We used the classification tree approach in Classification and Regression Trees (CART) with a binary target variable of HgbA1c >9.5 and 10 predictors: age, sex, emergency department visits, office visits, comorbidity index, dyslipidemia, hypertension, cardiovascular disease, retinopathy, end-stage renal disease. Unexpectedly, the most important variable associated with bad glycemic control is younger age, not the comorbiditity index or whether patients have related diseases. If we want to target diabetics with bad HgbA1c values, the odds of finding them is 3.2 times as high in those <65 years of age than those older. Data mining can discover novel associations that are useful to clinicians and administrators [corrected].

Adult↗

PubMed1977

Brittle diabetes in pregnancy.

In eight brittle diabetics the insulin requirement increased during successful pregnancies from 35 to 64 U./day (in 29 stable severe diabetics from 53 to 78 U./day). The within-day glycemic excursions were calculated as the mean of the three differences between four time points: fasting, one hour after breakfast, two hours after breakfast, and two hours after lunch. This parameter was constant throughout the pregnancy in nondiabetics (34-46 mg./100 ml.) and stable severe diabetics (55-72 mg./100 ml.). In brittle diabetics it dropped from 147 mg./100 ml. before the pregnancy and 153 mg./ 100 ml. at eight weeks to 85 mg./100 ml. at 36 weeks. The between-day variability was calculated as the mean glycemic difference between two successive days at the four points of time noted above. It was very low in nondiabetics (49-53 mg./100 ml.). In brittle diabetics it decreased from 127 mg./100 ml. before pregnancy and 120 mg./100 ml. at eight weeks to 46-55 mg./100 ml. at 24-36 weeks. This shows that brittleness substantially decreased in the second half of pregnancy.

Adult↗

PubMedDate not supplied

Psychosocial predictors of self-care behaviors (compliance) and glycemic control in non-insulin-dependent diabetes mellitus.

This study assessed potential psychosocial correlates of self-care behaviors (compliance) and of glycemic control in a community sample of 184 people diagnosed as having non-insulin-dependent (type II) diabetes mellitus. Four different diabetes self-care behaviors were studied (medication taking, glucose testing, diet, and exercise), and glycemic control was assessed by glycosylated hemoglobin analyses. Multiple measures were collected within each of several categories of psychosocial variables including knowledge, stress, depression, anxiety, diabetes-specific health beliefs, and social support. Findings indicate that approximately 25% of the variance in self-care behaviors can be explained by psychosocial and demographic variables. In contrast, psychosocial variables were not significant predictors of level of glycemic control. The diabetes-specific psychosocial measures of health beliefs and social support were the most consistent and strongest predictors of self-care behavior across the different regimen areas studied. Possible reasons for these findings, limitations of the study, and directions for future research are discussed.

Adult↗

PubMed1999

Impact of the work environment on glycemic control and adaptation to diabetes.

OBJECTIVE: To evaluate quantitatively whether the work environments of adults with diabetes relate to the adequacy of metabolic control and/or to the individual's adaptation to diabetes and to explore qualitatively the interactions between an individual's life at work and ways of coping with diabetes. RESEARCH DESIGN AND METHODS: A total of 129 insulin-requiring adults who were employed outside of the home were assessed on a single occasion. They completed two work system measures (The Work Environment Scale and The Work Apgar Scale) and two quality-of-life measures (The Diabetes Quality of Life Scale and The Appraisal of Diabetes Scale). Subjects also participated in a semi-structured interview concerning the interaction of work and diabetes. Glycemic control was assessed by using HbAlc results. Demographic data (age, sex, diabetes type, duration of diabetes, number of diabetes-related medical complications) were gathered from the charts. RESULTS: Concerning glycemic control, neither of the work system measures was a significant predictor of HbAlc. Concerning psychosocial adaptation, supervisor support was found to be a significant predictor of positive appraisal and diabetes-related satisfaction. Involvement and coworker cohesion also predicted aspects of diabetes-related quality of life. Interview themes showed that for a minority (18%), diabetes affected choice of work and that for a majority (60%), diabetes affected relationships at work and raised financial/job concerns (49%). Most adjust their diet, blood glucose testing, and exercise regimen through work-related modifications. CONCLUSIONS: For insulin-treated adults with diabetes, work system variables do not directly relate to glycemic control, but they do relate to psychosocial adaptation. Future work should examine further the specific aspects of the workplace that might affect adaptation, with the goal being to develop worksite interventions that target not only the employee with diabetes but also their supervisors and coworkers.

Adaptation, Physiological↗

PubMed1996

Phosphotyrosine protein phosphatases and diabetic pregnancy: an association between low molecular weight acid phosphatase and degree of glycemic control.

Low molecular weight acid phosphatase encoded by the highly polymorphic locus ACP1 is a member of the protein-tyrosin phosphatase family (PTPases) which plays an essential role in the control of receptor signalling through phosphotyrosine pathways. Recent experiments have shown that purified rat liver ACP, corresponding to human ACP1, is able to hydrolyze a phosphotyrosine-containing synthetic peptide corresponding to the 1146-1158 sequence of the human insulin receptor, and shows a high affinity for it. This prompted us to analyze the degree of glycemic control in relation to ACP1 genetic variability in a sample of 214 diabetic pregnant women including IDDM, NIDDM and gestational diabetes. The ACP1 genotype was also determined in 482 non-diabetic pregnant women. In diabetic women glycemic levels in the last trimester of pregnancy appear to be significantly associated with the ACP1 genotype, and correlate positively with ACP1 enzymatic activity. The data suggest that quantitative variations of ACP1 may influence the clinical manifestations of diabetic disorders, and call for further studies on the role of this enzyme in the modulation of insulin-receptor phosphotyrosine pathways.

Acid Phosphatase↗

PubMed1998

Management of patients with type 2 diabetes by pharmacists in primary care clinics.

OBJECTIVE: To determine the impact of clinical pharmacists involved in direct patient care on the glycemic control of patients with type 2 diabetes mellitus. DESIGN: Eligible patients included those with type 2 diabetes who received insulin or were initiated on insulin therapy by the pharmacists and were willing to perform self-monitoring of blood glucose. The pharmacists provided diabetes education, medication counseling, monitoring, and insulin initiation and/or adjustments. All initial patient interactions with the pharmacists were face-to-face. Thereafter, patient-pharmacist interactions were either face-to-face or telephone contacts. SETTING: Two primary care clinics in a university-affiliated Veterans Affairs Medical Center. PARTICIPANTS: Study subjects were patients with type 2 diabetes who were referred to the pharmacists by their primary care providers for better glycemic control. OUTCOME MEASURES: Primary outcome variables were changes from baseline in glycosylated hemoglobin, fasting blood glucose, and random blood glucose measurements. Secondary outcomes were the number and severity of symptomatic episodes of hypoglycemia, and the number of emergency room visits or hospitalizations related to diabetes. Twenty-three veterans aged 65-9.4 years completed the study. Fifteen (65%) patients were initiated on insulin by the pharmacists; 8 (35%) were already using insulin. Patients were followed for a mean-SD of 27-10 weeks. Glycosylated hemoglobin, fasting blood glucose concentrations, and random blood glucose concentrations significantly decreased from baseline by 2.2% (p = 0.00004), 65 mg/dL (p < 0.01), and 82 mg/dL (p = 0.00001), respectively. Symptomatic hypoglycemic episodes occurred in 35% of patients. None of these episodes required physician intervention. CONCLUSIONS: This study demonstrates that pharmacists working as members of interdisciplinary primary care teams can positively impact glycemic control in patients with type 2 diabetes requiring insulin.

Aged↗

PubMed2002

Care-related risk factors for chronic diabetic complications in developing countries: a case from Egypt.

This work was the second phase of a wider study aiming at defining a plan for the improvement of health care services for diabetic patients and to decrease the incidence of its complications. The aim of this phase of the study was to define preventable risk factors for chronic diabetic complications, especially care-related factors. A total of 472 diabetic patients with chronic complications were compared with 528 control patients, free from complications, in a multicentric case-control study. Multivariate logistic regression analysis revealed that diabetic patients over 49 y of age, and female gender were more likely to develop chronic diabetic complications. Among clinical variables, type and duration of diabetes, glycemic control, and hypertension were significant predictors of diabetic complications. Regarding patient and system practices, non-health-insurance, need of help to reach health care facility, irregularity of follow-up visits and attending more than one clinic for follow-up, sources of health information other than physician and nurse, non-practicing leisure physical activities, and smoking were statistically significant risk factors. The study helped to identify preventable risk factors for serious complications of diabetes. It also identified groups of patients who needed priorities of screening programmes for potential development of complications since they were likely to develop such type of complications.

Case-Control Studies↗

PubMed2003

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus.

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5%, NISDR = 33.3%) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8%; NISDR = 100%, control = 4.2%). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat.

Alloxan↗

PubMed2004

Glycemic index, glycemic load, and carbohydrate intake in relation to risk of distal colorectal adenoma in women.

Case-control studies and a cohort study have shown inconsistent associations between a high glycemic index or a high glycemic load and risk of colorectal cancer. These dietary variables have not been examined in relation to risk of colorectal adenoma. We thus examined the associations between dietary glycemic index, glycemic load, and carbohydrate intake with risk of adenoma of the distal colon or rectum among 34,428 US women who were initially free of cancer or polyps, who completed a semi-quantitative food-frequency questionnaire in 1980, and who underwent endoscopy from 1980 through 1998. 1,715 adenoma cases (704 large adenomas, 894 small adenomas, 1,277 distal colon adenomas, and 504 rectal adenomas) were documented during 18 years of follow-up. Dietary glycemic index, glycemic load, and carbohydrate intake were not related to risk of total colorectal adenoma after adjustment for age and established risk factors [relative risk (RR) for extreme quintiles of glycemic index = 1.11, 95% confidence interval (CI) 0.94-1.32, P for trend = 0.66; RR for glycemic load = 0.92, 95% CI 0.76-1.11, P for trend = 0.63; RR for carbohydrate intake = 0.90, 95% CI 0.73-1.11, P for trend = 0.64]. In addition, no significant associations were found for large or small adenoma, distal colon or rectal adenoma, or across strata of body mass index. Our findings do not support the hypothesis that a high glycemic index diet, a high glycemic load diet, or high carbohydrate intake overall are associated with risk of colorectal adenoma.

Adenomatous Polyps↗

PubMed1998

Family environment, glycemic control, and the psychosocial adaptation of adults with diabetes.

OBJECTIVE: To evaluate whether the family system variables of adults with diabetes relate to the adequacy of metabolic control or the psychosocial adaptation to the illness. RESEARCH DESIGN AND METHODS: A total of 150 insulin-requiring adults were assessed on a single occasion. They completed two family system measures (the Family Environment Scale [FES] and the Diabetes Family Behavior Checklist [DFBC]), two quality-of-life measures (the Diabetes Quality of Life Scale and the Medical Outcomes Study Health Survey-36), and one measure of cognitive appraisal (the Appraisal of Diabetes Scale). Glycemic control was assessed using HbA1c results. Demographic data (age, sex, diabetes type, duration of diabetes, and number of diabetes-related medical complications) were gathered from the patients' charts. RESULTS: Concerning glycemic control, none of the family system measures were significant predictors of HbA1c. Older age and longer duration of diabetes predicted higher HbA1c values. For psychosocial adaptation, when family members behaved in ways that supported the diabetes care regimen (measured by the DFBC), the individual with diabetes was more satisfied with his or her adaptation to the illness and reported less interference in role function due to emotional problems. Family cohesion (measured by the FES) also related to better physical function. Women reported higher levels of diabetes satisfaction. The Appraisal of Diabetes Scale predicted glycemic control and psychosocial adaptation. CONCLUSIONS: For insulin-treated adults with diabetes, family system variables do not relate to glycemic control, but they do relate to psychosocial adaptation. Future work should explore the impact of family-centered interventions on adaptation, sex differences in adaptation, and the use of the Appraisal of Diabetes Scale as a first-line clinical screening tool.

Adaptation, Psychological↗

PubMedDate not supplied

Social support, self-efficacy, and outcome expectations: impact on self-care behaviors and glycemic control in Caucasian and African American adults with type 2 diabetes.

PURPOSE: The purpose of this study was to examine the relationships of psychosocial variables (social support, self-efficacy, and outcome expectations) to diabetes self-care behaviors and glycemic control in Caucasian and African American adults with type 2 diabetes. METHODS: Study participants were scheduled for outpatient visits at 1 of 3 clinical sites in the southeastern United States. All 91 participants completed 4 self-report measures: Social Support Questionnaire (SSQ), Self-efficacy Questionnaire (SEQ), Outcome Expectancy Questionnaire (OEQ), and The Diabetes Activities Questionnaire (TDAQ) at the time of the clinic visit. Long-term glycemic control was assessed by glycosylated hemoglobin analyses at the time of the clinic visit. Pearson product-moment correlations were used to determine whether significant relationships existed between scores on the SSQ, SEQ, OEQ, and TDAQ and glycosylated hemoglobin values. Two-sample t tests were used to detect differences in scores on the self-report measures and glycosylated hemoglobin values between the 2 racial groups. RESULTS: In all participants, no significant relationships were found between (1) social support and self-care behaviors and (2) self-efficacy and self-care behaviors. Self-care behaviors were significantly, positively correlated with outcome expectancy scores for the total group and for African Americans. No significant relationships were found between (1) social support and glycemic control, (2) self-efficacy and glycemic control, and (3) outcome expectations and glycemic control. African Americans reported less social support satisfaction than Caucasians did. CONCLUSIONS: Psychosocial variables investigated in this study were not related to health outcomes of type 2 diabetes. Caucasians and African Americans were similar in these variables. It is important to investigate the relationships between other variables (eg, age, duration of diabetes, education) and self-care behaviors and glycemic control. Although African Americans experience higher rates of diabetes-related complications than Caucasians do, this may possibly be due to other factors (eg, heredity, financial barriers, inadequate health care). Additional investigations to study the relationships of these variables to diabetes control are warranted.

Black People↗

PubMed1999

The effect of particle size of whole-grain flour on plasma glucose, insulin, glucagon and thyroid-stimulating hormone in humans.

OBJECTIVE: Although it is well known that consumption of whole-grain foods with higher fiber content results in beneficial health effects, most Americans usually prefer bread made with white flour. Changes in bread texture and undesirable intestinal responses have been reported as reasons for avoiding consumption of whole-grain foods or high-fiber menus. The purpose of this study was to determine whether consumption of bread made with ultra-fine-ground whole-grain wheat flour retained beneficial effects while reducing undesirable effects. METHODS: Twenty-six men and women, 31 to 55 years of age, consumed glucose solutions or bread made with traditional white, conventional whole-grain wheat (WWF), or ultra-fine whole-grain wheat (UFWF) flour (1 g carbohydrate/kg body weight) in a Latin square design after two days of controlled diet. The effect on glycemic response was determined by comparing blood variables, after a tolerance test with white bread, WWF bread, and UFWF bread, with those after a glucose tolerance test. RESULTS: Men and women had similar responses to all tolerances except postprandial TSH. Glucose and insulin levels one half hour after the glucose load were significantly higher than after any of the bread tolerances. Glucose, but not insulin, areas under the curve were significantly higher after the glucose load than areas after the three breads. Consumption of UFWF resulted in glucose and insulin responses, as well as areas under the curve, similar to those after consumption of conventional whole-wheat bread. CONCLUSION: The particle size of whole grain wheat flour did not substantially affect glycemic responses.

Adult↗

PubMed2002

Physical activity and colon cancer: confounding or interaction?

PURPOSE: Although physical activity has been consistently inversely associated with colon cancer incidence, the association of physical activity with other diet and lifestyle factors that may influence this association is less well understood. Confounding and effect modification are examined to better understand the physical activity and colon cancer association. METHODS: Based on hypothesized biological mechanisms whereby physical activity may alter risk of colon cancer, we evaluated confounding and effect modification using data collected as part of a case-control study of colon cancer (N = 1993 cases and 2410 controls). We examined associations between total energy intake, fiber, calcium, fruit and vegetables, red meat, whole grains as well as dietary patterns along with cigarette smoking, alcohol consumption, BMI, and use of aspirin and/or NSAIDs and physical activity. RESULTS: No confounding was observed for the physical activity and colon cancer association. However, differences in effects of diet and lifestyle factors were identified depending on level of physical activity. Most striking were statistically significant interactions between physical activity and high-risk dietary pattern and vegetable intake, in that the relative importance of diet was dependent on level of physical activity. The predictive model of colon cancer risk was improved by using an interaction term for physical activity and other variables, including BMI, cigarette smoking, energy intake, dietary fiber, dietary calcium, glycemic index, lutein, folate, vegetable intake, and high-risk diet rather than using models that included these variables as independent predictors with physical activity. In populations where activity levels are high, the estimate of risk associated with high vegetable intake was 0.9 (95% CI 0.6-1.3), whereas in more sedentary populations the estimate of risk associated with high vegetable intake was 0.6 (95% CI 0.5-0.9). CONCLUSIONS: Physical activity plays an important role in the etiology of colon cancer. Its significance is seen by its consistent association as an independent predictor of colon cancer as well as by its impact on the odds ratios associated with other factors. Given these observations, it is most probable that physical activity operates through multiple biological mechanisms that influence the carcinogenic process.

Adult↗