Interaction between genes and lifestyle factors on obesity.

Obesity originates from a failure of the body-weight control systems, which may be affected by changing environmental influences. Basically, the obesity risk depends on two important mutually-interacting factors: (1) genetic variants (single-nucleotide polymorphisms, haplotypes); (2) exposure to environmental risks (diet, physical activity etc.). Common single-nucleotide polymorphisms at candidate genes for obesity may act as effect modifiers for environmental factors. More than 127 candidate genes for obesity have been reported and there is evidence to support the role of twenty-two genes in at least five different populations. Gene-environment interactions imply that the synergy between genotype and environment deviates from either the additive or multiplicative effect (the underlying model needs to be specified to appraise the nature of the interaction). Unravelling the details of these interactions is a complex task. Emphasis should be placed on the accuracy of the assessment methods for both genotype and lifestyle factors. Appropriate study design (sample size) is crucial in avoiding false positives and ensuring that studies have enough power to detect significant interactions, the ideal design being a nested case-control study within a cohort. A growing number of studies are examining the influence of gene-environmental interactions on obesity in either epidemiological observational or intervention studies. Positive evidence has been obtained for genes involved in adiposity, lipid metabolism or energy regulation such as PPARgamma2 (Pro12Ala), beta-adrenoceptor 2 (Gln27Glu) or uncoupling proteins 1, 2 and 3. Variants on other genes relating to appetite regulation such as melanocortin and leptin receptors have also been investigated. Examples of some recently-identified interactions are discussed

Low-fat dairy consumption and reduced risk of hypertension: the Seguimiento Universidad de Navarra (SUN) cohort

BACKGROUND: Some observational studies have shown a beneficial effect of dairy consumption on blood pressure, especially in overweight and relatively young (<40 y) persons. However, no results from prospective studies conducted in a free-living population exist that show this association in middle-aged adults. OBJECTIVE: The aim of the present study was to assess whether total, low-fat, and whole-fat dairy consumption was associated prospectively with the risk of hypertension. DESIGN: This was a prospective study conducted in 5880 university graduates in Spain, aged >20 y in 2000 (mean age: 37 y), free of hypertension and cardiovascular disease at baseline, and followed-up with mailed questionnaires for a median of 27 mo. Dairy consumption was assessed with a previously validated semiquantitative food-frequency questionnaire. RESULTS: One hundred eighty new cases of hypertension were identified. The hazard ratio of hypertension between extreme quintiles of low-fat dairy product consumption was 0.46 (95% CI: 0.26, 0.84; P for trend = 0.02) after adjustment for the main known risk factors for hypertension and several dietary factors. No significant association between whole-fat dairy products or total calcium intake and incident hypertension was seen. CONCLUSION: In this Mediterranean cohort, low-fat dairy consumption, but not whole-fat dairy consumption, was associated with a lower risk of incident hypertension

Psychoeducation as a strategy to improve family support perceived from patient with alcohol dependence and personality disorder

The aim of this study was to prospectively analyze the impact of psychoeducation with relatives of addicted patients with personality disorders. We measured the impact of the psychoeducational intervention using a self-report questionnaire designed to assess perceived familiar support. The sample was composed by 37 patients with alcohol dependence following outpatient treatment. They underwent a cognitive-behavioral therapy relapse prevention program especially tailored for addicted individuals with comorbid personality disorders. 56.8% of patients followed individual therapy, and 43.2% followed group therapy. The relatives of the subgroup patients following group therapy simultaneously received the psychoeducational intervention. The analyses of the familiar support questionnaire across treatment showed a significant difference between groups as a function of treatment modality. Patients whose relatives followed the psychoeducational intervention had greater perception of familiar support throughout the treatment process

Incidence of Hypertension in a Cohort of Spanish University Graduates:The SUN Study

Hypertension is a major public health problem. However, no estimates of age- and sex-specific incidences are available for the Spanish population. Our objective was to estimate the incidence of hypertension in a cohort of university graduates in Spain. We followed up 5648 individuals aged 25-65 years who were initially free of hypertension, diabetes, and cardiovascular disease for a median of 30 months. New diagnoses of hypertension were identified using mailed questionnaires. We validated the self-reported diagnosis of hypertension. In 18 250 person-years of follow-up, we identified 248 new cases of hypertension. The unadjusted incidences of hypertension in women and men were 8.2 per 1000 person-years (95% CI, 6.7-10.1) and 21.8 per 1000 person-years (95% CI, 18.6-25.4), respectively. The cumulative probability of receiving a medical diagnosis of hypertension by the age of 65 years was 50% among women and 72% among men. In conclusion, we have provided new evidence confirming that hypertension is one of the most important public health problems in Spain

Evaluación de la política comercial sobre el mercado del sorgo en México, 2000

La fuerte dependencia de las importaciones desde Estados Unidos y la reciente polémica en relación con los efectos negativos del Tratado de Libre Comercio de América del Norte, justifican la evaluación del impacto de políticas comerciales alternativas sobre el mercado del sorgo (Sorghum vulgare Pers) en México. Para analizar estos efectos se validó un modelo de programación cuadrática para producción, consumo e importaciones del grano de mayo de 1999 a abril de 2000. Los resultados del modelo validado indican que en 1999/2000, la producción, las importaciones y el consumo de sorgo fueron 6.1, 4.6 y 10.7 millones t. Si en 1999/2000 se hubiera permitido la importación de sólo 2.5 millones t, la producción y el consumo de sorgo hubieran sido mayor y menor en 1.4 y 0.7 millones de t, en relación con los niveles observados en ese año. Por el contrario, si se hubiera permitido el libre comercio, la producción hubiera sido 5.4 millones t, en tanto el consumo y las importaciones habrían aumentando en 0.3 y 1.0 millones t, en relación con los niveles de 1999/2000. Los beneficiados con la política de restricción de las importaciones habrían sido los productores, y los perjudicados los importadores y los consumidores. Con la política de libre comercio los beneficiados hubieran sido los consumidores e importadores, en tanto que los productores habrían resultado menos perjudicados

Determinants of the adherence to an "a priori" defined Mediterranean dietary pattern

Background: A prospective cohort study with university level participants was initiated to study the effect of Mediterranean diet on health. Aims: The objective of this study was to identify possible lifestyle and socioeconomic variables associated with the consumption of a Mediterranean dietary pattern (MDP). Method: This analysis includes 1587 males and 2260 females. MDP was defined “a priori” by summing the standardized residuals of nutrients and foods after adjusting a regression model using total energy intake as the independent variable. Multiple regression and non-parametric locally weighted regression models were adjusted with the relative adherence to the MDP as the dependent variable in males and females. Results: Women were more compliant than men with the MDP (Coefficient regression (b) = 4.1; Confidence Interval (CI) 95 % = 3.2 to 4.9). The compliance with the MDP was significantly poorer among younger participants both in men and women (p < 0.001 in men and in women). Participants who were more physically active were more likely to fulfill the traditional MDP (p = 0.01 in men and p < 0.001 in women). Conclusions: Our findings provide evidence supporting the progressive departure from the traditional MDP in younger and highly educated subjects of the Mediterranean area. A more active life-style is associated with a better compliance with the MDP

Interacción entre genotipo y nutrición: interpretación de estudios epidemiológicos

Epidemiological methods are increasingly used to assess the role of genetic factors and their interaction with environmental factors, in the occurrence of diseases in populations. Nutrition is one of the most relevant components of the interaction between the human being and the environment. Therefore, the interaction between susceptibility genotypes and nutritional risk factors has a great importance in the study of several chronic diseases. The aim of this article is to review different epidemiologic study designs and basic methods of analysis commonly used in the evaluation of the interaction between nutritional and genetic factors. These study designs and analytical methods are equally valid for the assessment of genotype-environment or genotype-genotype interaction

Daily physical activity and macronutrient distribution of low-calorie diets jointly affect body fat reduction in obese women.

Inadequate dietary patterns and sedentary lifestyles are believed to be important factors in predisposing people to obesity. This study analyzed the potential interaction between habitual physical activity and the carbohydrate (CHO)-fat distribution in 2 hypocaloric diets and the impact of such interplay on body composition changes. Forty healthy obese women, 20–50 years old, were randomly assigned to a high- or low-CHO energy-restricted diet, which was low or high in fat, respectively, during 10 weeks. Baseline and final measurements were performed to assess dietary habits, resting metabolic rate, and body composition changes. Physical activity was measured with a triaxial accelerometer and with a questionnaire. There were no significant differences in anthropometric and metabolic variables between both dietary groups at baseline. However, there was a positive correlation between total free-living physical activity and arm muscle preservation after 10 weeks (r = 0.371; p = 0.024). Interestingly, an interaction between macronutrient (CHO–fat distribution) intake and physical activity was found, since less-active subjects with a high-CHO–low-fat diet showed a greater fat loss than those more active with a lower-CHO–high-fat diet, whereas more-active subjects with a high-CHO–low-fat diet showed a smaller fat loss than those receiving a low-CHO–high-fat diet. Physical activity and the macronutrient content of energyrestricted diets, when designed to promote body fat mass reduction, should be considered together to better predict the outcome

Consumo de jamón curado e incidencia de eventos cardiovasculares, hipertensión arterial o ganancia de peso

Fundamento y objetivo: El jamón curado es uno de los alimentos característicos de la dieta mediterránea española. Sin embargo, no existe ningún estudio epidemiológico prospectivo que haya valorado sus efectos sobre la salud humana. Nuestro objetivo fue evaluar la asociación entre el consumo de jamón curado y la incidencia de hipertensión arterial, enfermedad cardiovascular y/o ganancia de peso. Sujetos y método: En una cohorte epidemiológica prospectiva y dinámica de 13.293 graduados universitarios (Proyecto SUN) se analizó la incidencia de enfermedad cardiovascular, hipertensión arterial y la ganancia de peso a lo largo de un seguimiento máximo de 6 años. Se ajustaron modelos de regresión de Cox para estimar hazard ratios (riesgos relativos [RR]) tras ajustar por posibles factores de confusión. Resultados: El consumo de jamón en los niveles más altos (> 4 raciones/semana) no presentaba asociación con la incidencia de eventos cardiovasculares (RR=1,02; [IC 95%: 0,44-2,39]), tras ajustar por edad, sexo, ingesta energética total y patrón dietético, en comparación con los consumos inferiores a una vez por semana. Al repetir esta comparación para la hipertensión, y tras ajustar por edad, sexo, ingesta energética total e índice de masa corporal, se encontró un RR = 0.74 (IC 95%: 0.55-1.01). En la comparación del cambio de peso medio anual entre estas mismas categorías extremas de consumo (=4 raciones) se encontró una diferencia no significativa de 0,033 kg (IC 95%: -0,041 a +0,107) en la ganancia media de peso al año tras ajustar por sexo, edad, tabaco, actividad física e índice de masa corporal inicial. Conclusiones: Los resultados de esta cohorte no proporcionan evidencia de que el consumo de jamón curado se asocie a mayor riesgo cardiovascular, de hipertensión arterial o de ganancia de peso.Background and objective: Cured ham is a characteristic food in Spanish Mediterranean diet. However, no prospective epidemiologic study assessing its effects on human health is available. Our aim was to assess the association between the consumption of cured ham and cardiovascular disease, hypertension or weight gain. Subjects and Method: In a prospective and dynamic epidemiologic cohort composed exclusively of university graduates (the SUN Project, n=13,293), we analyzed the incidence of cardiovascular disease, hypertension or average yearly weight gain after a maximum follow-up of 6 years. Cox (proportional hazards) regression models were fitted to estimate hazard ratios (relative risks [RR]) after adjusting for potential confounding. Results: No association was found between higher levels of consumption of cured ham (> 4 servings/week) and the incidence of cardiovascular disease (RR=1.02; [95%CI]: 0.44-2.39), in analyses adjusted for age, sex, total energy intake and dietary pattern, compared to the consumption of less than one serving a week. When we repeated this comparison for the incidence of hypertension, and adjusting for age, sex, total energy intake and body mass index, the RR was 0.74 (95% CI: 0.55-1.01). In the comparison of average yearly weight gain between these extreme categories of cured ham consumption (=4 servings/week) a non-significant difference of 0.033 kg (95% CI: -0.041 to 0.107) was found after adjusting for sex, age, smoking, physical activity, and baseline body mass index. Conclusions: The results of this cohort study do not support any association between the consumption of cured ham and a higher risk of cardiovascular disease, hypertension or weight gain

The Mediterranean diet protects against waist circumference enlargement in 12Ala carriers for the PPARgamma gene: 2 years' follow-up of 774 subjects at high cardiovascular risk.

The PPARgamma gene regulates insulin sensitivity and adipogenesis. The Pro12Ala polymorphism of this gene has been related to fat accumulation. Our aim was to analyse the effects of a 2-year nutritional intervention with Mediterranean-style diets on adiposity in high-cardiovascular risk patients depending on the Pro12Ala polymorphism of the PPARgamma gene. The population consisted of a substudy (774 high-risk subjects aged 55-80 years) of the Prevención con Dieta Mediterránea (PREDIMED) randomised trial aimed at assessing the effect of the Mediterranean diet for CVD prevention. There were three nutritional intervention groups: two of them of a Mediterranean-style diet and the third was a control group advised to follow a conventional low-fat diet. All the participants were genotyped by PCR-restriction fragment length polymorphism (RFLP). The results showed that carriers of the 12Ala allele allocated to the control group had a statistically significant higher change in waist circumference (adjusted difference coefficient = 2.37 cm; P = 0.014) compared with wild-type subjects after 2 years of nutritional intervention. This adverse effect was not observed among 12Ala carriers allocated to both Mediterranean diet groups. In diabetic patients a statistically significant interaction between Mediterranean diet and the 12Ala allele regarding waist circumference change was observed ( - 5.85 cm; P = 0.003). In conclusion, the Mediterranean diet seems to be able to reduce waist circumference in a high-cardiovascular risk population, reversing the negative effect that the 12Ala allele carriers of the PPARgamma gene appeared to have. The beneficial effect of this dietary pattern seems to be higher among type 2 diabetic subjects