Martin Lajous

Determinants of Prevalence, Acquisition, and Persistence of Human Papillomavirus in Healthy Mexican Military Men

Background: Human papillomavirus (HPV) infection is sexually transmitted, but the nature of the infection in males is poorly understood. We sought to identify determinants of HPV infection, acquisition, and persistence in 1,030 healthy military men in Mexico. Methods: From July 2000 to July 2003, trained interviewers administered a questionnaire, conducted a genital examination, and collected samples. The presence of multiple HPV types in genital cells from the urethra, urethral meatus, scrotum, penile shaft, and coronal sulcus was evaluated. At baseline 1,030 participants and after 1-year follow-up 336 individuals were sampled using a highly sensitive DNA reverse blot strip assay. Results: HPV prevalence was 44.6%; infection with high-risk types was observed in 34.8% participants and 51.1% were multiply infected. After 1-year follow-up, 165 men remained free of HPV, 68 cleared their infection, 45 acquired one, and 37 remained infected with the same HPV type. The period prevalence was 50.9%, the incidence rate was 17.9/1,000 men-months [95% confidence interval (95% CI), 13.0-23.9], clearance was 54%, and persistence was 29.4%. At baseline, the number of partners before age 20 years, a history of a sexually transmitted disease, and the presence of condilomas significantly increased the association with HPV infection. Having anal intercourse with males was associated with the risk of acquiring a HPV infection (odds ratio, 5.2; 95% CI, 1.2-23). The odds ratio for persistent infection was 0.10 (95% CI, 0-0.87) in men who reported being circumcised compared with those who did not. Conclusions: High-risk sexual behavior increases the risk of HPV infection in males, whereas circumcision may lower the risk of persistence.

Folate, Vitamin B6, and Vitamin B12 Intake and the Risk of Breast Cancer Among Mexican Women

Background: High intake of folate, vitamin B6, and vitamin B12 have been hypothesized to lower the risk for breast cancer. We conducted a population-based case-control study to evaluate the risk for breast cancer among Mexican women with relatively low vitamin intakes. Methods: We included 475 women (median age, 53 years; range, 23-87 years) diagnosed with incident breast cancer through six hospitals in Mexico City and interviewed them to obtain data on breast cancer risk factors and their usual diet using a food frequency questionnaire. We selected 1,391 (median age, 49 years; range, 18-82 years) controls from the Mexico City population using a national sampling frame. Results: Compared with women in the lowest quartile, the odds ratio for breast cancer for women in the highest quartile of folate intake was 0.64 [95% confidence intervals (CI), 0.45-0.90; P, test for trend = 0.009] and 0.32 (95% CI, 0.22-0.49; P, test for trend < 0.0001) for vitamin B12 intake. Among postmenopausal women, intakes of folate and vitamin B12 were associated with a lower risk of breast cancer and those associations were stronger than among premenopausal women. The inverse association of folate and breast cancer was stronger among women who consumed a high level of vitamin B12 as compared with women consuming diets low in vitamin B12. No association was observed for vitamin B6 intake. Conclusions: In this population, high intakes of folate and vitamin B12 were independently associated with decreased breast cancer risk, particularly among postmenopausal women. (Cancer Epidemiol Biomarkers Prev 2006;15(3):443–8)

Body mass index, diabetes, and mortality in French women: explaining away a “paradox”

Background: Obesity is associated with increased mortality in the general population but, paradoxically, with decreased mortality in persons with diabetes. Methods: Among 88,373 French women participating in the E3N-EPIC study who were free of diabetes in 1990, we estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality for body mass index (BMI) levels by diabetes status. Results: During an average 16.7 years of follow-up, 2421 cases of diabetes were identified and 3750 deaths occurred. For overweight/obese versus normal-weight women, the HR of mortality was 1.42 (95% CI = 1.32–1.53) in women without diabetes and 0.69 (0.40–1.18) in women with incident diabetes. As BMI increased, mortality among women without diabetes increased and that among women with diabetes decreased. Conclusions: We found the obesity “paradox” among women with and without incident diabetes in the same population. Selection bias may be a simple explanation for this “paradox.”

Glycemic load, glycemic index, and the risk of breast cancer among Mexican women.

Objective: The amount and composition of dietary carbohydrates is a major determinant of postprandial blood glucose and insulin, and risk of breast cancer has been positively associated with plasma levels of insulin and insulin-like growth factor 1. We sought to evaluate dietary glycemic load (GL) and overall glycemic index (GI) in relation to breast cancer risk in Mexican women.Methods: We examined dietary GL and overall GI and breast cancer risk among 475 women with histologically-confirmed breast cancer and a random sample of 1391 women from Mexico City households. Diet was assessed using a food frequency questionnaire adapted to the Mexican population.Results: The multivariate adjusted or for all women comparing the highest quartile of dietary GL with the lowest quartile was 1.62 (95% CI 1.13–2.32; p-test for trend = 0.02) with a significant trend. In postmenopausal women, the multivariate adjusted or comparing the extreme quartiles was 2.18 (95% CI 1.34–3.55; p-test for trend=0.005). Overall GI was not significantly associated with risk of breast cancer.Conclusion: High intake of rapidly absorbed carbohydrate appears to play an important role in the risk of breast cancer in Mexican women.

Adherence to predefined dietary patterns and incident type 2 diabetes in European populations: EPIC-InterAct Study

Few studies have investigated the relationship between predefined dietary patterns and type 2 diabetes incidence; little is known about the generalisability of these associations. We aimed to assess the association between predefined dietary patterns and type 2 diabetes risk in European populations. From among a case-cohort of 12,403 incident diabetes cases and 16,154 subcohort members nested within the prospective European Prospective Investigation into Cancer and Nutrition study, we used data on 9,682 cases and 12,595 subcohort participants from seven countries. Habitual dietary intake was assessed at baseline with country-specific dietary questionnaires. Two diet-quality scores (alternative Healthy Eating Index [aHEI], Dietary Approaches to Stop Hypertension [DASH] score) and three reduced rank regression (RRR)-derived dietary-pattern scores were constructed. Country-specific HRs were calculated and combined using a random-effects meta-analysis. After multivariable adjustment, including body size, the aHEI and DASH scores were not significantly associated with diabetes, although for the aHEI there was a tendency towards an inverse association in countries with higher mean age. We observed inverse associations of the three RRR-derived dietary-pattern scores with diabetes: HRs (95% CIs) for a 1-SD difference were 0.91 (0.86, 0.96), 0.92 (0.84, 1.01) and 0.87 (0.82, 0.92). Random-effects meta-analyses revealed heterogeneity between countries that was explainable by differences in the age of participants or the distribution of dietary intake. Adherence to specific RRR-derived dietary patterns, commonly characterised by high intake of fruits or vegetables and low intake of processed meat, sugar-sweetened beverages and refined grains, may lower type 2 diabetes risk.Aims/hypothesisFew studies have investigated the relationship between predefined dietary patterns and type 2 diabetes incidence; little is known about the generalisability of these associations. We aimed to assess the association between predefined dietary patterns and type 2 diabetes risk in European populations.MethodsFrom among a case-cohort of 12,403 incident diabetes cases and 16,154 subcohort members nested within the prospective European Prospective Investigation into Cancer and Nutrition study, we used data on 9,682 cases and 12,595 subcohort participants from seven countries. Habitual dietary intake was assessed at baseline with country-specific dietary questionnaires. Two diet-quality scores (alternative Healthy Eating Index [aHEI], Dietary Approaches to Stop Hypertension [DASH] score) and three reduced rank regression (RRR)-derived dietary-pattern scores were constructed. Country-specific HRs were calculated and combined using a random-effects meta-analysis.ResultsAfter multivariable adjustment, including body size, the aHEI and DASH scores were not significantly associated with diabetes, although for the aHEI there was a tendency towards an inverse association in countries with higher mean age. We observed inverse associations of the three RRR-derived dietary-pattern scores with diabetes: HRs (95% CIs) for a 1-SD difference were 0.91 (0.86, 0.96), 0.92 (0.84, 1.01) and 0.87 (0.82, 0.92). Random-effects meta-analyses revealed heterogeneity between countries that was explainable by differences in the age of participants or the distribution of dietary intake.Conclusions/interpretationAdherence to specific RRR-derived dietary patterns, commonly characterised by high intake of fruits or vegetables and low intake of processed meat, sugar-sweetened beverages and refined grains, may lower type 2 diabetes risk.

Processing of meats and cardiovascular risk: time to focus on preservatives

Dietary guidelines emphasize selecting lean (low-fat) meats to reduce saturated fat and cholesterol, but growing evidence suggests that health effects may relate to other ingredients, such as sodium, heme iron, or L-carnitine. Understanding how meats influence health, and on which nutrients this relationship depends, is essential to advise consumer choices, set guidelines, and inform food reformulations. A recent study published in BMC Medicine involving 448,568 participants in 10 European countries, provides important evidence in this regard. After multivariate adjustment, intake of unprocessed red meat was not significantly associated with total or cause-specific mortality; conversely, intake of processed meat was associated with a 30% higher rate of cardiovascular disease (CVD) (per 50 g/day, relative risk 1.30, 95% confidence interval 1.17 to 1.45) and also higher cancer mortality. These findings are consistent with our previous meta-analysis, based on smaller studies, showing strong associations of processed meats, but not unprocessed meats, with CVD. Preservatives are the notable difference; the calculated blood-pressure effects of sodium differences (around 400% higher in processed meats) explain most of the observed higher risk. Although unprocessed red meats seem to be relatively neutral for CVD, healthier choices are available, including fish, nuts, legumes, fruits, and vegetables. Public-health guidance should prioritize avoidance of processed meats, including the low-fat deli meats currently marketed as healthy choices, and the food industry should substantially reduce sodium and other preservatives in processed meats.See related research article here http://www.biomedcentral.com/1741-7015/11/63.

Use of Cumulative Incidence of Novel Influenza A/H1N1 in Foreign Travelers to Estimate Lower Bounds on Cumulative Incidence in Mexico

Background An accurate estimate of the total number of cases and severity of illness of an emerging infectious disease is required both to define the burden of the epidemic and to determine the severity of disease. When a novel pathogen first appears, affected individuals with severe symptoms are more likely to be diagnosed. Accordingly, the total number of cases will be underestimated and disease severity overestimated. This problem is manifest in the current epidemic of novel influenza A/H1N1. Methods and Results We used a simple approach to leverage measures of incident influenza A/H1N1 among a relatively small and well observed group of US, UK, Spanish and Canadian travelers who had visited Mexico to estimate the incidence among a much larger and less well surveyed population of Mexican residents. We estimate that a minimum of 113,000 to 375,000 cases of novel influenza A/H1N1 have occurred in Mexicans during the month of April, 2009. Such an estimate serves as a lower bound because it does not account for underreporting of cases in travelers or for nonrandom mixing between Mexican residents and visitors, which together could increase the estimates by more than an order of magnitude. Conclusions We find that the number of cases in Mexican residents may exceed the number of confirmed cases by two to three orders of magnitude. While the extent of disease spread is greater than previously appreciated, our estimate suggests that severe disease is uncommon since the total number of cases is likely to be much larger than those of confirmed cases.

Should Patients with Chronic Disease Be Told to Gain Weight? The Obesity Paradox and Selection Bias

Obesity is associated with lower mortality in individuals with chronic disease.(1) This counterintuitive inverse association—the “obesity paradox”(2)—has been described in patients with cardiovascular disease, diabetes, hip fracture and even Chagas’ disease. If obese individuals with chronic diseases live longer, should we start advising them to gain rather than lose weight?

Processed and unprocessed red meat consumption and hypertension in women

BACKGROUND High processed red meat consumption is associated with increased risk of cardiovascular disease. The high sodium content of processed red meat could increase blood pressure and explain the association with cardiovascular disease. OBJECTIVE We evaluated the relation between the consumption of unprocessed and processed red meat and incident hypertension. DESIGN In a prospective cohort of 44,616 disease-free French women who responded to a validated dietary questionnaire, we observed 10,256 incident cases of hypertension between 1993 and 2008. Cases were identified through self-reports of diagnosed or treated hypertension. Multivariate Cox regression models were adjusted for age, education, smoking, physical activity, body mass index, menopause, menopausal hormone therapy, and alcohol, bread, coffee, and fruit and vegetable consumption. RESULTS Women who consumed ≥5 servings of processed red meat/wk (50 g = 1 serving) had a 17% higher rate of hypertension than that of women who consumed <1 serving/wk (HR: 1.17; 95% CI: 1.09, 1.26; P-trend = 0.0002). No association was observed between unprocessed red meat consumption and hypertension. When women who consumed ≥5 servings of unprocessed red meat/wk (100 g = 1 serving) were compared with women who consumed <1 serving unprocessed red meat/wk, the multivariate HR was 0.99 (95% CI: 0.91, 1.08; P-trend = 0.63). CONCLUSIONS In this large prospective cohort of French women, we observed an association between the consumption of processed red meat and hypertension. We observed no association for unprocessed red meat consumption and hypertension.

Processed and Unprocessed Red Meat Consumption and Incident Type 2 Diabetes Among French Women

OBJECTIVE To evaluate the relation of processed and unprocessed red meat and incident type 2 diabetes. RESEARCH DESIGN AND METHODS We conducted a prospective study among 66,118 disease-free French women with dietary information from a validated questionnaire. Between 1993 and 2007, we identified 1,369 cases of incident diabetes. Multivariate analyses were adjusted for age, education, region, smoking, BMI, hypertension, hypercholesterolemia, physical activity, parental history of diabetes, menopause, hormone replacement therapy, alcohol, calories, n-3 fatty acids, carbohydrates, coffee, fiber, and fruits and vegetables. RESULTS Comparing the highest category of processed meat intake, ≥5 servings/week (median, 48 g/day), to the lowest, <1 serving/week (median, 5 g/day), processed meat was significantly associated with incident diabetes (hazard ratio 1.30 [95% CI 1.07–1.59], P trend = 0.0007; for 1 serving/day, 1.29 [1.14–1.45]). Unprocessed red meat was not associated with diabetes. CONCLUSIONS In this large prospective cohort of French women, a direct association was observed only for processed red meat and type 2 diabetes.