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

Prevención cardiovascular y de la osteoporosis con terapia hormonal sustitutiva

Se recomienda actualmente que todo médico -sea cual sea su especialidad- aproveche la oportunidad que supone la atención clínica a cualquier mujer postmenopáusica o que se halle en torno a la menopausia para aconsejarle acerca de los beneficios y riesgos que supone la terapia hormonal sustitutiva (THS) con estrógenos y progesterona. Una vez que sea adecuadamente informada de estos beneficios y riesgos, debe ser la propia mujer quien decida si va a iniciar o no esta terapia, teniendo en cuenta no sólo su propio perfil de riesgo sino también sus preferencias. Los beneficios más claros se refieren a la reducción del riesgo de osteoporosis y de fracturas, así como al control y prevención de algunos síntomas frecuentes en la menopausia. Para prevenir la osteoporosis se requiere un uso continuado de IaTHS. También existen cada vez más argumentos que sugieren una reducción del riesgo de un primer episodio coronario. No obstante, no hay pruebas de que laTHS sea útil en la prevención secundaria de la cardiopatía isquémica o aporte alguna protección frente a los accidentes cerebrovasculares. Las desventajas más importantes de la THS se refieren a un mayor riesgo de hiperplasia de endometrio y de cáncer endometrial cuando se usan estrógenos solos, sin combinarlos con progestágenos. También existe un pequeño incremento del riesgo de cáncer de mama cuando se prolonga la THS, también cuando se asocian progestágenos

Dieta mediterránea y enfermedad cardiovascular: resultados del estudio piloto del proyecto SUN

Fundamento: La dieta mediterránea ha sido propuesta como modelo de patrón dietético para la prevención de la cardiopatía isquémica. El proyecto SUN (“Seguimiento Universidad de Navarra”) es un estudio epidemiológico prospectivo de cohortes, que se inició en el año 2000 y que va dirigido a identificar determinantes dietéticos y no dietéticos implicados en estas enfermedades. La viabilidad del proyecto, se comprobó con un estudio piloto en dos fases. Métodos: La primera fase del estudio piloto contó con la participación de voluntarios en los que se valoraron las exposiciones dietéticas y no dietéticas mediante un cuestionario autoadministrado y por entrevista personal. Para la segunda fase, se seleccionó una muestra aleatoria de 600 graduados y se les envió el cuestionario por correo. Para estimar la variabilidad inter-sujetos se calcularon los percentiles 10, 25, 50, 75 y 90 de consumo para los principales alimentos y nutrientes considerados. Resultados: Los participantes entendieron y respondieron adecuadamente los cuestionarios. El tiempo medio empleado en contestar el cuestionario fue de 55,0 minutos (IC 95%=50,7-59,3). Se encontró una amplia variabilidad inter-sujetos entre los percentiles 10 y 90 en el consumo de los principales alimentos que pueden considerarse indicadores de la dieta mediterránea, como son el aceite de oliva, las frutas, las verduras y el vino. Conclusiones: La submuestra presentó una participación relativamente aceptable. Se halló un patrón de dieta mediterránea con una variabilidad inter-sujetos suficientemente amplia como para poder encontrar asociaciones entre el consumo de alimentos y la incidencia de las principales enfermedades cardiovasculares

Efectos del cannabis sobre la salud mental en jóvenes consumidores

Esta es la segunda parte de una revisión sobre los efectos adversos que presenta el consumo de cannabis sobre la salud de los jóvenes. La primera parte trató sobre los efectos adversos para la salud física y esta segunda parte trata de los efectos adversos sobre la salud psíquica. El cannabis ha sido considerado a veces como una droga relativamente menos peligrosa que otras, y además se le han atribuido otras finalidades distintas de las recreativas, buscando efectos terapéuticos (analgésico, anticonvulsivo, sedante, antidepresivo, etc.). Sin embargo, en los últimos años existe una creciente evidencia epidemiológica de la existencia de efectos adversos sobre la salud psíquica a medio y largo plazo, además de los derivados de la dependencia y abstinencia. En el presente artículo se ha realizado una búsqueda bibliográfica y se han analizado especialmente grandes estudios epidemiológicos más recientes que han evaluado los efectos sobre la salud mental en consumidores jóvenes. Se presenta una puesta al día del estado actual del conocimiento epidemiológico de la relación entre cannabis y enfermedad psíquica

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

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

The SUN cohort study (Seguimiento University of Navarra)

Objective: Cohort study (the SUN project) to identify dietary determinants of hypertension, diabetes, obesity and coronary heart disease (CHD), among other conditions. Design: The SUN project is a Mediterranean dynamic prospective follow-up (cohort) study assessing participants every 2 years. The recruitment started in 2000 and it is permanently open (this is a dynamic cohort). A preliminary case–control study of myocardial infarction was also conducted, selecting incident cases of myocardial infarction and matched hospital controls. Setting: The SUN study is conducted in Spain with university graduates, most of them being former students of the University of Navarra. The case–control study was conducted in three tertiary hospitals in the city of Pamplona (Spain). Subjects: The case–control study included 171 cases and 171 controls. We have currently enrolled more than 17 500 participants in the SUN cohort. Approximately 7500 of them were enrolled less than 2 years ago, and have not received yet the invitation to complete the 2-year follow-up assessment. The follow-up rate for the first 10 000 participants approaches 90%. Results: The case–control study found inverse associations between olive oil (or adherence to a Mediterranean food pattern) and myocardial infarction. In the SUN cohort, after 28.5 months of follow-up a higher adherence to a Mediterranean food pattern rich in olive oil was associated with a reduced risk of hypertension, though the results were statistically significant only among men. Conclusions: The SUN study and the accompanying case–control study support the benefits of a Mediterranean diet and olive oil against CHD and hypertension

Benefits of the Mediterranean diet beyond the Mediterranean Sea and beyond food patterns

Abundant and growing evidence has accrued to demonstrate that the traditional Mediterranean diet is likely to be the ideal dietary pattern for the prevention of cardiovascular disease. A landmark randomized trial (PREDIMED) together with many well-conducted long-term observational prospective cohort studies support this causal effect. A new, large British cohort study by Tong et al. assessing the association between adherence to the Mediterranean diet and cardiovascular disease was recently published in BMC Medicine. Using a superb methodology, they followed-up 23,902 participants for 12.2 years on average and observed several thousand incident cases. The results of this cohort study showed a significant beneficial effect of the Mediterranean diet on cardiovascular events. These findings support the transferability of this dietary pattern beyond the shores of the Mediterranean Sea. The authors provided measures of population impact in cardiovascular prevention and estimated that 19,375 cases of cardiovascular death would be prevented each year in the UK by promoting the Mediterranean Diet

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