Relationship between systemic markers of inflammation and serum beta-carotene levels

BACKGROUND

Low serum levels of beta-carotene have been associated with increased risk of cancer and cardiovascular disease. However, in clinical trials, supplementation of the diet with beta-carotene either had no benefit or caused harm. This pattern of findings raises the possibility that confounding by other factors might explain the association between serum beta-carotene level and disease risk.

METHODS

We used data from 14 470 current smokers, ex-smokers, and never smokers aged 18 years or older who participated in the Third National Health and Nutrition Examination Survey to assess the relationship between serum beta-carotene and markers of inflammation (C-reactive protein and white blood cell count).

RESULTS

After adjustment for beta-carotene intake and other factors, geometric mean levels of serum beta-carotene for individuals with undetectable (< 0.22 mg/dL), mildly elevated (0.22-0.99 mg/dL), and clinically elevated (> or =1.0 mg/dL) C-reactive protein levels were 18.0, 16.1, and 13.6 microg/dL, respectively, in never smokers; 18.1, 15.7, and 13.9 microg/dL in ex-smokers; and 11.3, 10.2, and 9.4 microg/dL in current smokers (P< .001 for all). In corresponding analyses, white blood cell count was also inversely related to serum beta-carotene concentration (P< .05 for all).

CONCLUSIONS

The strong and inverse association of serum beta-carotene level with C-reactive protein level and white blood cell count suggests that the relationship between serum beta-carotene concentration and disease risk might be confounded by inflammation. More broadly, for beta-carotene and likely other nutrients, it seems unwise to interpret biomarker data as prima facie evidence of dietary intake without a more complete understanding of the physiologic processes that affect nutrient levels.

Motivations for exercise and weight loss among African-American women: focus group results and their contribution towards program development

OBJECTIVE

African-American women are more likely to be sedentary and maintain higher body weights compared with Caucasian women, although some are physically active and able to maintain weight loss. To develop effective intervention strategies, we need to understand why some women are successful.

DESIGN

We conducted focus groups on four distinct groups of African-American women (currently physically active; currently sedentary; successful weight loss for > or = 1 year; unsuccessful weight loss) to explore motivations and intervention strategies. Open-ended questions, probes, and visual aids were used to stimulate discussions. Transcripts of sessions were read to highlight themes and concepts.

RESULTS

Results indicated that motivators for the exercisers to start exercising were health concerns, weight control, stress reduction, and the influence of others. Motivators to continue exercising were feeling good and having energy. In contrast, the sedentary women reported that social support and enjoyment would be motivating. Both groups reported that physically active women conveyed the image of high energy and self-esteem. The successful weight loss women employed strategies that allowed them to eat a variety of foods and were less likely to 'diet'. The unsuccessful women referred to 'going on a diet' and were more likely to label foods as 'good' or 'bad'. They reported feeling tired and thought that losing weight would give them more energy.

CONCLUSION

This information was used to develop two culturally appropriate interventions for African-American women, which is presented. Conducting formative research in study design protocols can provide an important role in intervention development.

A comparison of the Yale Physical Activity Survey with other physical activity measures

PURPOSE

The purpose of this study was to determine associations of the Yale Physical Activity Survey (YPAS) with the Stanford 7-d physical activity recall (PAR) and several physiologic measures, both cross-sectionally and longitudinally.

METHODS

Participants were 59 individuals (45% African-American, 79% women) between the ages of 60 and 80 yr who were enrolled in a clinical trial. From the YPAS, total time in activity, estimated weekly energy expenditure, and indices of vigorous activity, leisurely walking, moving, standing, sitting, and an overall summary index were determined. From the PAR, daily energy expenditure, and hours spent in light, moderate, and hard/very hard activities were estimated. Physiologic measurements included estimated VO2max, resting pulse rate, and body mass index (BMI).

RESULTS

Weekly energy expenditure, total time in activity, and the summary index correlated with daily energy expenditure at baseline (Spearman correlations = 0.37, 0.30, 0.33, respectively, Ps < 0.01) and time in moderate activity (r = 0.37, 0.29, 0.39, Ps < 0.01). The vigorous index was also significantly correlated with daily energy expenditure and time in light, moderate, and hard/very hard activity. The summary, moving, and standing indices correlated with VO2max (Ps < 0.05) and BMI (Ps < 0.05). Change in physical activity determined from the PAR correlated with change in most YPAS dimensions, although few correlations were statistically significant.

CONCLUSIONS

The global activities and the vigorous activity index determined from the YPAS correlated with corresponding measures of the PAR. The validity of the YPAS for light-intensity activities is less clear, although optimal validation measures for light-intensity activity are yet to be defined. The ability of the YPAS to detect change in physical activity shows some promise, but data from this study are insufficient to be conclusive.

Low serum cholesterol and haemorrhagic stroke in men: Korea Medical Insurance Corporation Study

BACKGROUND

In some prospective studies, haemorrhagic stroke occurs more frequently in individuals with low serum cholesterol than in those with higher concentrations. We aimed to determine whether low total serum cholesterol is an independent risk factor for haemorrhagic stroke (intracerebral haemorrhage and subarachnoid haemorrhage) in South Korea, a country that has a population with relatively low concentrations of total serum cholesterol.

METHODS

We measured total serum cholesterol and other cardiovascular risk factors in 114,793 Korean men, aged between 35-59 years in 1990 and 1992, in a prospective observational study. We used data obtained in 1992 for smoking and alcohol consumption. We divided total serum cholesterol into quintiles (<4.31 mmol/L, 4.31-<4.74, 4.74-<5.16, 5.16-<5.69 and > or = 5.69). Our primary outcomes were hospital admissions and deaths from intracerebral and subarachnoid haemorrhage in a 6 year follow-up between 1993 and 1998.

FINDINGS

528 men had a haemorrhagic stroke--372 intracerebral and 98 subarachnoid haemorrhage--and 58 were unspecified strokes. The relative risks of intracerebral haemorrhage in each quintile of total serum cholesterol (lowest to highest were: 1.22 (95% CI 0.88-1.69); 0.86 (0.60-1.21); 1.08 (0.78-1.48); and 1.03 (0.75-1.41). The corresponding relative risks for subarachnoid haemorrhage were: 1.44 (0.76-2.73); 1.13 (0.59-2.20); 1.21 (0.64-2.29); and 1.12 (0.59-2.14).

INTERPRETATION

Low total serum cholesterol is not an independent risk factor for either intracerebral or subarachnoid haemorrhagic stroke in Korean men.

Effects of reduced sodium intake on hypertension control in older individuals: results from the Trial of Nonpharmacologic Interventions in the Elderly (TONE)

BACKGROUND

Few trials have evaluated the effects of reduced sodium intake in older individuals, and no trial has examined the effects in relevant subgroups such as African Americans.

PATIENTS AND METHODS

The effects of sodium reduction on blood pressure (BP) and hypertension control were evaluated in 681 patients with hypertension, aged 60 to 80 years, randomly assigned to a reduced sodium intervention or control group. Participants (47% women, 23% African Americans) had systolic BP less than 145 mm Hg and diastolic BP less than 85 mm Hg while taking 1 antihypertensive medication. Three months after the start of intervention, medication was withdrawn. The primary end point was occurrence of an average systolic BP of 150 mm Hg or more, an average diastolic BP of 90 mm Hg or more, the resumption of medication, or a cardiovascular event during follow-up (mean, 27.8 months).

RESULTS

Compared with control, mean urinary sodium excretion was 40 mmol/d less in the reduced sodium intervention group (P<.001); significant reductions in sodium excretion occurred in subgroups defined by sex, race, age, and obesity. Prior to medication withdrawal, mean reductions in systolic and diastolic BPs from the reduced sodium intervention, net of control, were 4.3 mm Hg (P<.001) and 2.0 mm Hg (P =.001). During follow-up, an end point occurred in 59% of reduced sodium and 73% of control group participants (relative hazard ratio = 0.68, P<.001). In African Americans, the corresponding relative hazard ratio was 0.56 (P =.005); results were similar in other subgroups. In dose-response analyses, end points were progressively less frequent with greater sodium reduction (P for trend =.002).

CONCLUSION

A reduced sodium intake is a broadly effective, nonpharmacologic therapy that can lower BP and control hypertension in older individuals.

Coffee consumption and serum lipids: a meta-analysis of randomized controlled clinical trials

Coffee drinking has been associated with increased serum cholesterol levels in some, but not all, studies. A Medline search of the English-language literature published prior to December 1998, a bibliography review, and consultations with experts were performed to identify 14 published trials of coffee consumption. Information was abstracted independently by two reviewers using a standardized protocol. With a random-effects model, treatment effects were estimated by pooling results from individual trials after weighting the results by the inverse of total variance. A dose-response relation between coffee consumption and both total cholesterol and LDL cholesterol was identified (p < 0.01). Increases in serum lipids were greater in studies of patients with hyperlipidemia and in trials of caffeinated or boiled coffee. Trials using filtered coffee demonstrated very little increase in serum cholesterol. Consumption of unfiltered, but not filtered, coffee increases serum levels of total and LDL cholesterol.

Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group

BACKGROUND

The effect of dietary composition on blood pressure is a subject of public health importance. We studied the effect of different levels of dietary sodium, in conjunction with the Dietary Approaches to Stop Hypertension (DASH) diet, which is rich in vegetables, fruits, and low-fat dairy products, in persons with and in those without hypertension.

METHODS

A total of 412 participants were randomly assigned to eat either a control diet typical of intake in the United States or the DASH diet. Within the assigned diet, participants ate foods with high, intermediate, and low levels of sodium for 30 consecutive days each, in random order.

RESULTS

Reducing the sodium intake from the high to the intermediate level reduced the systolic blood pressure by 2.1 mm Hg (P<0.001) during the control diet and by 1.3 mm Hg (P=0.03) during the DASH diet. Reducing the sodium intake from the intermediate to the low level caused additional reductions of 4.6 mm Hg during the control diet (P<0.001) and 1.7 mm Hg during the DASH diet (P<0.01). The effects of sodium were observed in participants with and in those without hypertension, blacks and those of other races, and women and men. The DASH diet was associated with a significantly lower systolic blood pressure at each sodium level; and the difference was greater with high sodium levels than with low ones. As compared with the control diet with a high sodium level, the DASH diet with a low sodium level led to a mean systolic blood pressure that was 7.1 mm Hg lower in participants without hypertension, and 11.5 mm Hg lower in participants with hypertension.

CONCLUSIONS

The reduction of sodium intake to levels below the current recommendation of 100 mmol per day and the DASH diet both lower blood pressure substantially, with greater effects in combination than singly. Long-term health benefits will depend on the ability of people to make long-lasting dietary changes and the increased availability of lower-sodium foods.

Long-term weight loss and changes in blood pressure: results of the Trials of Hypertension Prevention, phase II

BACKGROUND

Weight loss appears to be an effective method for primary prevention of hypertension. However, the long-term effects of weight loss on blood pressure have not been extensively studied.

OBJECTIVE

To present detailed results from the weight loss arm of Trials of Hypertension Prevention (TOHP) II.

DESIGN

Multicenter, randomized dinical trial testing the efficacy of lifestyle interventions for reducing blood pressure over 3 to 4 years. Participants in TOHP II were randomly assigned to one of four groups. This report focuses only on participants assigned to the weight loss (n = 595) and usual care control (n = 596) groups.

PATIENTS

Men and women 30 to 54 years of age who had nonmedicated diastolic blood pressure of 83 to 89 mm Hg and systolic blood pressure less than 140 mm Hg and were 110% to 165% of their ideal body weight at baseline.

INTERVENTION

The weight loss intervention included a 3-year program of group meetings and individual counseling focused on dietary change, physical activity, and social support

MEASUREMENTS

Weight and blood pressure data were collected every 6 months by staff who were blinded to treatment assignment

RESULTS

Mean weight change from baseline in the intervention group was -4.4 kg at 6 months, -2.0 kg at 18 months, and -0.2 kg at 36 months. Mean weight change in the control group at the same time points was 0.1, 0.7, and 1.8 kg. Blood pressure was significantly lower in the intervention group than in the control group at 6, 18, and 36 months. The risk ratio for hypertension in the intervention group was 0.58 (95% CI, 0.36 to 0.94) at 6 months, 0.78 (CI, 0.62 to 1.00) at 18 months, and 0.81 (CI, 0.70 to 0.95) at 36 months. In subgroup analyses, intervention participants who lost at least 4.5 kg at 6 months and maintained this weight reduction for the next 30 months had the greatest reduction in blood pressure and a relative risk for hypertension of 0.35 (CI, 0.20 to 0.59).

CONCLUSIONS

Clinically significant long-term reductions in blood pressure and reduced risk for hypertension can be achieved with even modest weight loss.

Nutrition-related cardiovascular risk factors in older people: results from the Third National Health and Nutrition Examination Survey

SETTING

In view of the recognized potential benefits of nutritional therapy in older persons, Congress is evaluating the coverage of nutritional services for Medicare beneficiaries.

OBJECTIVE

To estimate the number of older persons in the US who have one or more cardiovascular risk factors (hypertension, increased low density lipoprotein (LDL) cholesterol, and diabetes mellitus), for which nutritional therapy is recommended.

DESIGN

Cross-sectional analysis of adults, aged > or = 65, participating in the Third National Health and Nutrition Examination Survey (NHANES III).

MAIN OUTCOMES

The authors estimated the proportion of adults, aged > or = 65, with diabetes mellitus, increased LDL cholesterol, and/or hypertension. Efforts were made to assess whether obesity status, gender, race, and/or socioeconomic factors were associated with the prevalence of any or all three conditions.

RESULTS

Approximately 86% (20 million persons) in the US, aged > or = 65, have at least one of the index conditions. Whereas a higher body mass index (BMI) increased the likelihood of having any or all three conditions, 81% of persons of average body weight (BMI <25 kg/m2) had at least one condition. After adjusting for age, gender, BMI, marital status, and poverty index, blacks were more likely than whites to have any one condition (odds ratio (OR) = 3.0, P < .01) or all three conditions (OR = 2.3, P = .05).

CONCLUSIONS

Almost 90% of Americans aged > or = 65 have one or more nutrition-related cardiovascular risk factors. Improved nutritional interventions may be valuable especially for blacks, who have a higher prevalence of conditions requiring nutritional therapy.

The role of diet in the prevention and treatment of hypertension

An impressive body of evidence strongly supports the concept that multiple dietary factors influence blood pressure and that modification of diet can have powerful, beneficial effects on this highly prevalent, yet modifiable, cardiovascular risk factor. Dietary therapies with a proven ability to lower blood pressure include reduced sodium intake, weight loss, moderation of alcohol intake, increased potassium intake, and a diet that emphasizes fruits, vegetables, and low-fat dairy products that is low in fat and cholesterol. Several other dietary factors, such as an increased intake of protein or monounsaturated fatty acids, may also reduce blood pressure, but evidence to date is insufficient for policy recommendations. Still, widespread implementation of those therapies with a proven ability to lower blood pressure should have an enormous impact on the adverse patterns of blood pressure that remain highly prevalent in the United States and most other countries.

The methylenetetrahydrofolate reductase gene is associated with increased cardiovascular risk in Japan, but not in other populations

The methylenetetrahydrofolate reductase (MTHFR) gene has been associated with increased risk for cardiovascular disease in some, but not all studies. Our data sources included a MEDLINE search of the literature published before December 1998, a bibliography review, and expert consultation. Of 23 studies initially identified, 18 (9855 persons) met the inclusion criteria. Information on sample size, study design, Hardy-Weinberg equilibrium, method of genotype determination, plasma folate and homocysteine were abstracted by two reviewers using a standardized protocol. The overall odds ratio of the MTHFR gene on cardiovascular disease was estimated using the Mantel-Haenzel method. From 12 studies with angiographically-confirmed coronary artery disease (CAD), the overall odds ratio (OR) for CAD among those with heterozygous (V/A) was 1.3 (95% CI, 1.1-1.5), while it was 1.4 (1.2-1.6) for the homozygous mutant (V/V) compared to those with homozygous normal (A/A). However, the overall odds ratio for CAD among those with the V/V genotype versus A/A genotype was not statistically significant (OR: 1.1; 95% CI: 0.9-1.3) after excluding three Japanese studies. The corresponding OR for the three Japanese studies was 2.0 (1.6-2.7). For six studies with myocardial infarction (MI), the overall OR of MI was 1.0 (0.8-1.1) for those with the V/A genotype and 0.9 (0.7-1.1) for those with the V/V genotype, respectively; none of these ORs for MI was statistically significant. The MTHFR gene is associated with increased risk for CAD in Japan, but not in other populations.

Impact of pill organizers and blister packs on adherence to pill taking in two vitamin supplementation trials

The impact of pill organizers on pill taking was determined in the Trial of Antioxidant Vitamins C and E (TRACE) Study, a factorial trial of vitamin C and vitamin E supplementation in 184 individuals. Participants were recruited in 1996-1997 and randomized to one of two groups (pill organizer or no organizer) and to one of four supplement groups for 2 months. The pill count (observed/expected X 100%) distribution was similar in the organizer and no organizer group for both vitamins. Mean differences in changes in serum vitamin levels between active and placebo groups did not differ by pill organizer use. The impact of pill organizers and blister packs was compared in another trial, the Vitamins, Teachers, and Longevity (VITAL) Study, in 297 individuals randomized in 1993-1994 to receive study pills either in blister packs or in pill organizers and to take one of two supplements. Among those with lower adherence, the pill count distribution in the blister-pack group exceeded that in the organizer group. Mean differences in serum vitamin E levels between active and placebo groups did not differ by types of pill packaging. In summary, use of blister packs, but not pill organizers, improved adherence as measured by pill counts among those with lower adherence. Neither pill delivery system improved adherence as measured by serum vitamin levels.

The effect of dietary patterns on blood pressure control in hypertensive patients: results from the Dietary Approaches to Stop Hypertension (DASH) trial

To determine the impact of dietary patterns on the control of hypertension we studied the subgroup of 133 participants with systolic blood pressure (BP) of 140 to 159 mm Hg and/or diastolic BP of 90 to 95 mm Hg enrolled in the Dietary Approaches to Stop Hypertension (DASH) study. Participants were fed a control diet for a 3-week period and were then randomized to receive for 8 weeks either the control diet; a diet rich in fruits and vegetables, but otherwise similar to control; or a combination diet rich in fruits, vegetables, and low-fat dairy products, including whole grains, fish, poultry, and nuts, and reduced in fats, red meats, sweets, and sugar-containing beverages. Sodium intake and body weight were held constant throughout the study. The combination diet significantly reduced systolic BP (-11.4 mm Hg, P < .001) and diastolic BP (-5.5 mm Hg, P < .001). The fruits-and-vegetables diet also significantly reduced systolic BP (-7.2 mm Hg, P < .001) and diastolic BP (-2.8 mm Hg, P = .013). The combination diet produced significantly greater BP effects (P < .05) than the fruits-and-vegetables diet. Blood pressure changes were evident within 2 weeks of starting the intervention feeding. After the 8-week intervention period, 70% of participants eating the combination diet had a normal BP (systolic BP < 140 and diastolic BP < 90 mm Hg) compared with 45% on the fruits-and-vegetables diet and 23% on the control diet. In patients with hypertension, the DASH combination diet effectively lowers BP and may be useful in achieving control of Stage 1 hypertension.

Effect of dietary patterns on serum homocysteine: results of a randomized, controlled feeding study

BACKGROUND

Elevated blood levels of homocysteine are associated with an increased risk of atherosclerotic cardiovascular disease. Although numerous studies have assessed the impact of vitamin supplements on homocysteine, the effect of dietary patterns on homocysteine has not been well studied.

METHODS AND RESULTS

During a 3-week run-in, 118 participants were fed a control diet, low in fruits, vegetables, and dairy products, with a fat content typical of US consumption. During an 8-week intervention phase, participants were then fed 1 of 3 randomly assigned diets: the control diet, a diet rich in fruits and vegetables but otherwise similar to control, or a combination diet rich in fruits, vegetables, and low-fat dairy products and reduced in saturated and total fat. Between the end of run-in and intervention periods, mean change in homocysteine was +0.46 micromol/L in the control diet, +0.21 micromol/L in the fruits and vegetables diet (P=0.47 compared with control), and -0.34 micromol/L in the combination diet (P=0.03 compared with control, P=0.12 compared with the fruits and vegetables diet). In multivariable regression models, change in homocysteine was significantly and inversely associated with change in serum folate (P=0.03) but not with change in serum vitamin B(12) (P=0.64) or pyridoxal 5' phosphate, the coenzyme form of vitamin B(6) (P=0.83).

CONCLUSIONS

Modification of dietary patterns can have substantial effects on fasting levels of total serum homocysteine. These results provide additional insights into the mechanisms by which diet might influence the occurrence of atherosclerotic cardiovascular disease.

Relationship between skin color and blood pressure in egyptian adults: results from the national hypertension project

In many, but not all societies, dark skin color is associated with high blood pressure. Whether the association between skin color and blood pressure is independent of known determinants of blood pressure remains controversial. We examined the association between skin color and blood pressure in 835 Egyptian adults (370 men and 465 women) participating in the National Hypertension Project, a national survey of hypertension prevalence and blood pressure-related complications conducted in Egypt during 1991-1993. Skin color was assessed by measuring the concentration of cutaneous melanin in an unexposed area with the use of reflectance spectrophotometry. Higher concentrations of melanin were associated with lower body mass index, less education, manual labor (among men), and a lower urinary sodium-to-potassium ratio (among women). In multivariate regression analyses adjusted for age, body mass index, and education, there was a significant nonlinear association between blood pressure and skin color among women; in the lower to intermediate range of skin pigmentation, both systolic and diastolic blood pressures were higher in women with greater concentrations of cutaneous melanin. In men, blood pressure was not associated with skin color. When we used a subjective assessment of skin color, there was no significant difference in blood pressure between black-skinned Egyptians (predominantly of Nubian descent) and fair-skinned Egyptians for either gender. While the significant relationship in women appeared to be independent of known risk factors for hypertension, residual confounding may explain the association.

The effects of vitamin C and vitamin E on oxidative DNA damage: results from a randomized controlled trial

Oxidative DNA damage may be important in mutagenic, carcinogenic, and aging processes. Although it is plausible that antioxidant vitamins may reduce oxidative DNA damage, evidence from human studies has been sparse and inconsistent. We determined the short-term effects of vitamin C (500 mg/day) and vitamin E (400 IU d-alpha-tocopheryl acetate/day) supplements on oxidative DNA damage in a double-masked, placebo-controlled, 2x2 factorial trial in 184 nonsmoking adults. Mean duration of supplementation was 2 months. Oxidative DNA damage was measured by 24-h urinary excretion of 8-hydroxy-2'-deoxyguanosine (8-OHdG). At baseline, urinary 8-OHdG (mean +/- SE; ng/mg creatinine) was associated with race (15.6 +/- 0.8 in African Americans versus 20.3 +/- 1.2 in Caucasians, P = 0.001), prior antioxidant supplement use (18.6 +/- 0.8 in users versus 13.8 +/- 1.5 in non-users, P = 0.007), and regular exercise (19.2 +/- 1.1 in exercisers versus 16.6 +/- 0.9 in non-exercisers, P = 0.04). Fruit and vegetable intake and serum ascorbic acid were inversely associated with urinary 8-OHdG (P-trend = 0.02 and 0.016, respectively). The benefits of fruit and vegetable intake became evident with the consumption being at least three servings/day. At the end of supplementation, change from baseline in urinary 8-OHdG (mean +/- SE; ng/mg creatinine) was -0.6 +/- 1.4 (P = 0.61), 0.6 +/- 1.1 (P = 0.59), 0.5 +/- 1.0 (P = 0.61), and 1.6 +/- 1.4 (P = 0.27) in the placebo, vitamin C alone, vitamin E alone, and combined vitamins C and E groups, respectively. In overall and subgroup analyses, there was no significant main effect or interaction effect of the supplements on urinary 8-OHdG. In conclusion, supplementation of diet with vitamin C (500 mg/day) and vitamin E (400 IU d-alpha-tocopheryl acetate/day) had no significant main effect or interaction effect on oxidative DNA damage as measured by urinary 8-OHdG in nonsmoking adults. However, several aspects of a healthy lifestyle were associated with lower oxidative DNA damage.

Long-term effects of weight loss and dietary sodium reduction on incidence of hypertension

To examine the long-term effects of weight loss and dietary sodium reduction on the incidence of hypertension, we studied 181 men and women who participated in the Trials of Hypertension Prevention, phase 1, in Baltimore, Md. At baseline (1987 to 1988), subjects were 30 to 54 years old and had a diastolic blood pressure (BP) of 80 to 89 mm Hg and systolic BP <160 mm Hg. They were randomly assigned to one of two 18-month lifestyle modification interventions aimed at either weight loss or dietary sodium reduction or to a usual care control group. At the posttrial follow-up (1994 to 1995), BP was measured by blinded observers who used a random-zero sphygmomanometer. Incident hypertension was defined as systolic BP > or =160 mm Hg and/or diastolic BP > or =90 mm Hg and/or treatment with antihypertensive medication during follow-up. Body weight and urinary sodium were not significantly different among the groups at the posttrial follow-up. After 7 years of follow-up, the incidence of hypertension was 18.9% in the weight loss group and 40.5% in its control group and 22.4% in the sodium reduction group and 32.9% in its control group. In logistic regression analysis adjusted for baseline age, gender, race, physical activity, alcohol consumption, education, body weight, systolic BP, and urinary sodium excretion, the odds of hypertension was reduced by 77% (odds ratio 0.23; 95% confidence interval 0.07 to 0.76; P=0.02) in the weight loss group and by 35% (odds ratio 0.65; 95% confidence interval 0.25 to 1.69; P=0.37) in the sodium reduction group compared with their control groups. These results indicate that lifestyle modification such as weight loss may be effective in long-term primary prevention of hypertension.

Smoking and atherosclerotic cardiovascular disease in men with low levels of serum cholesterol: the Korea Medical Insurance Corporation Study

CONTEXT

Few studies have examined the interactive effects of smoking and serum cholesterol level on morbidity and mortality from cardiovascular dieseases. In East Asia, where the prevalence of smoking is among the highest in the world, morbidity and mortality from ischemic heart disease (IHD) is rapidly escalating.

OBJECTIVES

To determine whether cigarette smoking is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD) in the Republic of Korea (South Korea), a population that has relatively low levels of serum cholesterol, and to determine whether serum cholesterol levels modify the risk relationship between smoking and ASCVD.

DESIGN

Prospective cohort study with a follow-up period of 6 years (1993-1998).

SETTING AND SUBJECTS

A total of 106745 Korean men aged 35 to 59 years who received health insurance from the Korea Medical Insurance Corporation and who had biennial medical evaluations in 1990 and 1992.

MAIN OUTCOME MEASURES

Hospital admissions and deaths from IHD, cerebrovascular disease (CVD), and total ASCVD.

RESULTS

At baseline, 61389 (58%) were current cigarette smokers and 64482 (60%) had a total cholesterol level of less than 5.17 mmol/L (200 mg/dL). Between 1993 and 1998, 1006 IHD events (176 per 100000 person-years), 1364 CVD events (238 per 100000 person-years), and 716 other ASCVD events (125 per 100000 person-years) occurred. In multivariate Cox proportional hazard models controlling for age, hypertension, hypercholesterolemia, and diabetes, current smoking increased the risk of IHD (risk ratio [RR], 2.2; 95% confidence interval [CI], 1.8-2.8), CVD (RR, 1.6; 95% CI, 1.4-1.8), and total ASCVD (RR, 1.6; 95% CI, 1.5-1.8). For each outcome, there were significant dose-response relationships with amount and duration of smoking. Throughout the range of serum cholesterol levels, current smoking significantly increased the risk of IHD and CVD. In the lowest quartile of serum cholesterol levels (<4.42 mmol/L [171 mg/dL]), the RR from current smoking was 3.3 (95% CI, 1.7-6.2) for IHD and 1.6 (95% CI, 1.2-2.3) for CVD. There was no evidence of an interaction between smoking and serum cholesterol (P for interaction = .75, .87, and .92 for IHD, CVD, and total ASCVD, respectively).

CONCLUSIONS

This study demonstrates that in Korea smoking is a major independent risk factor for IHD, CVD, and ASCVD and that a low cholesterol level confers no protective benefit against smoking-related ASCVD.

Effect of dietary patterns on ambulatory blood pressure : results from the Dietary Approaches to Stop Hypertension (DASH) Trial. DASH Collaborative Research Group

We measured ambulatory blood pressure (ABP) in 354 participants in the Dietary Approaches to Stop Hypertension (DASH) Trial to determine the effect of dietary treatment on ABP (24-hour, day and night) and to assess participants' acceptance of and compliance with the ABP monitoring (ABPM) technique. After a 3-week run-in period on a control "typical" American diet, subjects (diastolic blood pressure [BP], 80 to 95 mm Hg; systolic BP, <160 mm Hg; mean age, 45 years) were randomly assigned to 1 of 3 diets for an 8-week intervention period: a continuation of the control diet; a diet rich in fruits and vegetables; and a "combination" diet that emphasized fruits, vegetables, and low-fat dairy products. We measured ABP at the end of the run-in and intervention periods. Both the fruit/vegetable and combination diets lowered 24-hour ABP significantly compared with the control diet (P<0. 0001 for systolic and diastolic pressures on both diets: control diet, -0.2/+0.1 mm Hg; fruit/vegetable diet, -3.2/-1.9 mm Hg; combination diet, -4.6/-2. 6 mm Hg). The combination diet lowered pressure during both day and night. Hypertensive subjects had a significantly greater response than normotensives to the combination diet (24-hour ABP, -10.1/-5.5 versus -2.3/-1.6 mm Hg, respectively). After correction for the control diet responses, the magnitude of BP lowering was not significantly different whether measured by ABPM or random-zero sphygmomanometry. Participant acceptance of ABPM was excellent: only 1 participant refused to wear the ABP monitor, and 7 subjects (2%) provided incomplete recordings. These results demonstrate that the DASH combination diet provides significant round-the-clock reduction in BP, especially in hypertensive participants.