The genetic determinants of plasma cholesterol and response to diet

Frequency of eating home cooked meals and potential benefits for diet and health: cross-sectional analysis of a population-based cohort study

BACKGROUND

Reported associations between preparing and eating home cooked food, and both diet and health, are inconsistent. Most previous research has focused on preparing, rather than eating, home cooked food; used small, non-population based samples; and studied markers of nutrient intake, rather than overall diet quality or health. We aimed to assess whether frequency of consuming home cooked meals was cross-sectionally associated with diet quality and cardio-metabolic health.

METHODS

We used baseline data from a United Kingdom population-based cohort study of adults aged 29 to 64 years (n = 11,396). Participants self-reported frequency of consuming home cooked main meals. Diet quality was assessed using the Mediterranean Diet Score, Dietary Approaches to Stop Hypertension (DASH) score, fruit and vegetable intake calculated from a 130-item food frequency questionnaire, and plasma vitamin C. Markers of cardio-metabolic health were researcher-measured body mass index (BMI), percentage body fat, haemoglobin A1c (HbA1c), cholesterol and hypertension. Differences across the three exposure categories were assessed using linear regression (diet variables) and logistic regression (health variables).

RESULTS

Eating home cooked meals more frequently was associated with greater adherence to DASH and Mediterranean diets, greater fruit and vegetable intakes and higher plasma vitamin C, in adjusted models. Those eating home cooked meals more than five times, compared with less than three times per week, consumed 62.3 g more fruit (99% CI 43.2 to 81.5) and 97.8 g more vegetables (99% CI 84.4 to 111.2) daily. More frequent consumption of home cooked meals was associated with greater likelihood of having normal range BMI and normal percentage body fat. Associations with HbA1c, cholesterol and hypertension were not significant in adjusted models. Those consuming home cooked meals more than five times, compared with less than three times per week, were 28% less likely to have overweight BMI (99% CI 8 to 43%), and 24% less likely to have excess percentage body fat (99% CI 5 to 40%).

CONCLUSIONS

In a large population-based cohort study, eating home cooked meals more frequently was associated with better dietary quality and lower adiposity. Further prospective research is required to identify whether consumption of home cooked meals has causal effects on diet and health.

Age and sex differences in the relationship between inherited and lifestyle risk factors and subclinical carotid atherosclerosis: the Tromsø study

BACKGROUND

Ultrasound measurement of carotid artery intima-media thickness (IMT) is regarded as a valid index of atherosclerosis. Age and sex differences in the distribution of, and risk factors for, IMT have not been investigated thoroughly.

METHODS

In 1994-1995 a total of 6408 men and women aged 25-84 years living in the municipality of Tromsø, Norway, underwent ultrasound examination of carotid artery IMT and measurements of cardiovascular risk factors.

RESULTS

Age, systolic blood pressure, total cholesterol, HDL cholesterol, body mass index, and smoking were independent predictors of IMT in both sexes. Fibrinogen levels and physical activity were associated with IMT in men only, whereas triglyceride levels were associated with IMT independently of HDL cholesterol in women only. A family history of cardiovascular disease (CVD) was an independent predictor of IMT in both sexes, also when controlling for traditional CVD risk factors. The magnitude of the association between most risk factors and IMT did not differ depending on age, but the effects of physical activity and triglycerides were more pronounced at higher age.

CONCLUSION

These data suggest that there are significant age and sex differences in the distribution and the determinants of subclinical atherosclerosis.

An overview of genetic factors influencing plasma lipid levels and coronary artery disease risk

BACKGROUND

Coronary artery disease (CAD) is a major cause of morbidity and mortality in most Western countries and its origin involves a significant genetic component.

METHODS

Genetic and epidemiologic studies have been performed to identify factors that influence the CAD risk in the population.

RESULTS

The primary loci that have been demonstrated to be associated with increased CAD risk owing to genetic mutations include the low-density lipoprotein receptor, apolipoprotein B-100, and lipoprotein(a). Additional implicated loci include lipoprotein lipase, apolipoprotein CII, cholesteryl ester transfer protein, apolipoprotein AI, and lecithin-cholesterol acyl transferase.

CONCLUSIONS

Numerous mutations in known genes exert a major effect on CAD risk in some patients. However, in most patients with CAD, the genetic component is believed to be attributable to the aggregate effect of loci that, individually, exert only a minor influence on lipoprotein levels.

Compliance with and efficacy of treatment with pravastatin and cholestyramine: a randomized study on lipid-lowering in primary care

OBJECTIVES

Lipid-lowering drugs as 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors and cholestyramine are effective in reducing cardiovascular morbidity both in primary and secondary prevention. Patient compliance is an important determinant of the outcome of therapy. This study was designed to compare compliance with tolerance and lipid-lowering effectiveness of pravastatin and/or cholestyramine in primary care.

DESIGN

Nine hundred and eighty nine women and 1047 men were randomized to treatment at 100 primary-care centres in Sweden. After dietary intervention, an eligible patient was randomly assigned to one of four programs of daily treatment: group Q, 16 g cholestyramine, group QP, 8 g cholestyramine and 20 mg pravastatin, group P20, 20 mg pravastatin or group P40, 40 mg pravastatin.

RESULTS

In group Q, group QP, group P20 and group P40 the reductions in low density lipoprotein (LDL)-cholesterol were 26%, 36%, 27% and 32%. The dose actually taken was 91-95% of the prescribed for the pravastatin treatment groups and 77-88% for the cholestyramine groups. In the pravastatin and cholestyramine groups 76-78% and 44-53%, respectively, completed the trial. Only 8-27% of the patients reached a serum cholesterol target level of 5.2 mmol L-1. There was no difference in lipid-lowering effect between women and men.

CONCLUSION

Pravastatin alone is efficacious and compliance is high, independent of dose. Combined treatment with cholestyramine and pravastatin had a better cholesterol lowering effect (although not statistically significant) than 40 mg pravastatin. Despite this, only 8-27% of the patients actually reached a serum cholesterol level of 5.2 mmol L-1. No unexpected serious adverse events were detected in any of the treatment groups. As predicted, the gastrointestinal disturbances were more common on cholestyramine treatment. These two factors suggest that an increase in the dosage of the HMG-CoA reductase inhibitor may be appropriate. Results from other studies indicate that there also might be other positive effects of statin treatment beyond cholesterol lowering.

Do genetic determinates of ischaemic heart disease imply that prevention may become more difficult?

Favourable changes in environment and lifestyle in the community may lead to a situation in which genetic determinants of ischaemic heart disease assume greater importance. Does this imply that ischaemic heart disease becomes more difficult to prevent? Much of the role of the family history as a risk factor within populations may be explained by new genetic mutations. However, differences between populations are generally attributable to environmental differences. A model of gene-environment interaction implies that individuals or populations with genetic risk markers are both more susceptible and more responsive to environmental changes, including lifestyle and drugs, and thus, may be eminently treatable.