Decline of the relative risk of death associated with low employment grade at older age: the impact of age related differences in smoking, blood pressure and plasma cholesterol

STUDY OBJECTIVE

To explore whether the observed age related decline in the relative risk of death associated with low employment grade can be explained by the profiles of smoking, blood pressure and plasma cholesterol changing differently with age between the employment grades.

DESIGN

Prospective cohort study with 25 years of mortality follow up.

SETTING

Whitehall study.

PARTICIPANTS

There were 16,984 men aged 40 to 69 years at baseline with complete information on smoking, blood pressure and plasma cholesterol.

MAIN RESULTS

The relative risk of death associated with low employment grade decreased from 2.1 at 55-59 years of age to 1.3 at 85-89 years of age. Adjustment for smoking status and blood pressure, attenuated the age related decline of the relative risk by 18% and 3% respectively; adjustment for plasma cholesterol increased the decline by 3%. Taken together, these risk factors explain 20% of the observed age related decline.

CONCLUSIONS

A small part of the observed age related decline in the relative risk of death associated with low employment grade can be explained by differential changes in the profiles of smoking, blood pressure and plasma cholesterol with age between the employment grades.

Blood pressure and risk of dementia: results from the Rotterdam study and the Gothenburg H-70 Study

The association between blood pressure and dementia is debated. Results from population-based studies on blood pressure and dementia are inconclusive, and most are performed in subjects younger than 80 years of age. We examined the relation between blood pressure and dementia and the possible effect modification of this relation by age in a pooled dataset based on two prospective population-based studies. Subjects came from the Rotterdam study (n = 6,668), a longitudinal population-based study among subjects aged 55 years and over, and from the Gothenburg H-70 Study (n = 317), a study on subjects aged 85 years at baseline. Screening and diagnostic procedures for assessment of dementia were similar at baseline and follow-up and comparable between studies. We estimated relative risks of dementia using Cox proportional hazards regression analysis, adjusted for age, gender and study location. The average follow-up was 2.1 years. During this period, 196 subjects developed dementia. The risk of dementia decreased with increasing blood pressure level (per 10 mm Hg systolic blood pressure: RR = 0.93, 95% CI = 0.88-0.99; per 10 mm Hg diastolic blood pressure: RR = 0.89, 95% CI = 0.79-1.00). This association was confined to subjects who used anthypertensive medication. Persons who were demented at baseline had a stronger blood pressure decline during follow-up than those who were non-demented. This study suggests an inverse association between blood pressure and dementia risk in elderly persons on antihypertensive medication. Possibly, they may need higher blood pressure levels to maintain an adequate cerebral perfusion. Alternatively, lower blood pressure may be secondary to brain lesions in preclinical stages of dementia.

Arterial stiffness as underlying mechanism of disagreement between an oscillometric blood pressure monitor and a sphygmomanometer

Oscillometric blood pressure devices tend to overestimate systolic blood pressure and underestimate diastolic blood pressure compared with sphygmomanometers. Recent studies indicate that discrepancies in performance between these devices may differ between healthy and diabetic subjects. Arterial stiffness in diabetics could be the underlying factor explaining these differences. We studied differences between a Dinamap oscillometric blood pressure monitor and a random-zero sphygmomanometer in relation to arterial stiffness in 1808 healthy elderly subjects. The study was conducted within the Rotterdam Study, a population-based cohort study of subjects aged 55 years and older. Systolic and diastolic blood pressure differences between a Dinamap and a random-zero sphygmomanometer were related to arterial stiffness, as measured by carotid-femoral pulse wave velocity. Increased arterial stiffness was associated with higher systolic and diastolic blood pressure readings by the Dinamap compared with the random-zero sphygmomanometer, independent of age, gender, and average mean blood pressure level of both devices. The beta-coefficient (95% CI) was 0.25 (0.00 to 0.50) mm Hg/(m/s) for the systolic blood pressure difference and 0.35 (0.20 to 0.50) mm Hg/(m/s) for the diastolic blood pressure difference. The results indicate that a Dinamap oscillometric blood pressure device, in comparison to a random-zero sphygmomanometer, overestimates systolic and diastolic blood pressure readings in subjects with stiff arteries.

Hormone replacement therapy and peripheral arterial disease: the Rotterdam study

BACKGROUND

As the number of elderly women increases in Western society, peripheral arterial disease (PAD) is likely to become an increasing problem. Hormone replacement therapy, suggested to protect against coronary atherosclerosis, might also inhibit the development of PAD.

METHODS

The association between hormone replacement therapy and the presence of PAD was studied in a population-based study consisting of 2196 naturally menopausal women aged 55 to 80 years living in a suburban area of Rotterdam, the Netherlands. Peripheral arterial disease was defined as an ankle/arm systolic blood pressure index (ratio of the systolic blood pressure at the ankle to the systolic blood pressure at the arm) lower than 0.9.

RESULTS

Hormone replacement therapy for 1 year or longer was associated with a 52% decreased risk of PAD (odds ratio, 0.48 [95% confidence interval, 0.24-0.85]), while no association was found for therapy duration shorter than 1 year (odds ratio, 0.97 [95% confidence interval, 0.58-1.63) after adjustment for age, smoking, and socioeconomic status. Additional adjustment for body mass index, age at menopause, total cholesterol and high-density lipoprotein cholesterol, alcohol intake, and frequency of visits to health care facilities did not change the results.

CONCLUSION

The findings of this population-based study suggest that hormone replacement therapy given for a year or more is associated with a decreased risk of PAD among postmenopausal women.

The effect of hormone replacement therapy on arterial distensibility and compliance in perimenopausal women: a 2-year randomised trial

A single centre randomised placebo-controlled trial was performed to assess the 2-year effects of hormone replacement therapy compared to placebo on mechanical arterial properties in 99 perimenopausal women recruited from the general population. The trial was double-blind with respect to a sequential combined regimen of oral 17beta-oestradiol and desogestrel (17betaE(2)-D) and the placebo group and open with respect to combination of conjugated equine oestrogens and norgestrel (CEE-N). At baseline, distensibility and compliance of the common carotid artery were measured non-invasively with B-mode ultrasound and a vessel wall movement detector system, and the distensibility coefficient (DC) and compliance coefficient (CC) were calculated. Measurements were repeated after 6 and 24 months. Change in DC and CC in treatment groups was compared to placebo. After 24 months, changes for 17betaE(2)-D compared to placebo were -1.4x10(-3)/kPa (95% CI -4.4; 1.7, P=0.39) for DC and 0. 26 mm(2)/kPa (95% CI -0.01; 0.53, P=0.07) for CC. Changes for CEE-N compared to placebo were 0.4x10(-3)/kPa (95% CI -1.0; 1.9, P=0.79) and 0.11 mm(2)/kPa (95% CI -0.14; 0.37, P=0.40). For systolic blood pressure (SBP), diastolic blood pressure (DBP) and arterial lumen diameter no changes were found. In this study no significant differences in changes in distensibility and compliance were found between perimenopausal women using 17betaE(2)-D or CEE-N and women using placebo after 6 and 24 months.

Postmenopausal hormone therapy: less favourable risk-benefit ratios in healthy Dutch women

OBJECTIVES

To estimate the health effects of postmenopausal hormone therapy used for 10 or 20 years in a population of intermediate cardiovascular risk.

DESIGN

Using existing estimates of the effect of hormone therapy on rates of myocardial infarction, hip fracture and breast cancer, a proportional multistage life table was generated to calculate the effects of use for 10 and 20 years in a synthetic cohort of Dutch women aged 55 with an average and a high-risk profile for cardiovascular disease.

RESULTS

A woman of the general population who starts hormone therapy at age 55 for 10 years can prolong her life by 1 month and may postpone the occurrence of first incidence of one of the diseases under consideration by 2.4 months. One excess breast cancer case is likely to occur per 5-6 averted cases of first myocardial infarction or hip fracture. If she prolongs her use to 20 years, the gain of life expectancy and disease-free life expectancy is doubled. The risk-benefit ratio worsens to one extra breast cancer per 3-4 averted cases of the preventable diseases. For a woman with a high-risk profile, the gains in health are about twice as high as for her counterpart in the general population, and her risk-benefit ratio is also more favourable. Yet, the risk-benefit ratio still worsens for 20 as compared with 10 years of use.

CONCLUSIONS

Women from the general population in the Netherlands and similar populations can achieve only a modest gain in life expectancy by using hormones during 10 or 20 years following menopause. This is a consequence of the low incidence of myocardial infarction and hip fracture and the relatively high incidence of breast cancer before the age of 75. Women at increased cardiovascular risk can benefit more from hormone therapy. But even amongst these women, the risk of breast cancer incurred with long-term use offsets much of the benefit that could accrue from changing the risk of heart disease and hip fracture.

Progression of aortic calcification is associated with metacarpal bone loss during menopause: a population-based longitudinal study

offerosclerosis and osteoporosis are major causes of morbidity and mortality in postmenopausal women and have been suggested to be associated. No study has examined whether progression of atherosclerotic calcification is associated with bone loss. In the present study, we examined progression of aortic calcification, diagnosed by radiographic detection of calcified deposits in the abdominal aorta, in relation to metacarpal bone loss, as assessed by metacarpal radiogrammetry, during menopause. Initially premenopausal women (n=236), aged 45 to 57 years at baseline, were followed for 9 years. We additionally assessed the cross-sectional association between the extent of aortic calcification and metacarpal bone mass and density in 720 postmenopausal women. Twenty-five percent of women going through menopause showed progression of aortic calcification. The average loss of metacarpal bone mass among women with progression of aortic calcification was 3.2 mm(2), and their loss of metacarpal bone density was 7.2 mm(2) %, whereas in women without progression of aortic calcification, these losses were 2.0 mm(2) and 5.6 mm(2) %, respectively, adjusted for age and years of follow-up (P<0.05). Additional adjustment for age at menopause, body mass index, blood pressure, smoking, diabetes mellitus, and use of hormone replacement therapy, thiazide, and loop diuretics did not influence these results. In postmenopausal women, a graded inverse cross-sectional association between the extent of aortic calcification and metacarpal bone mass and density was found. In conclusion, our results indicate that progression of atherosclerotic calcification is associated with increased bone loss in women during menopause.

Variables of the insulin resistance syndrome are associated with reduced arterial distensibility in healthy non-diabetic middle-aged women

AIMS/HYPOTHESIS

The insulin resistance syndrome is related to arterial stiffness in diabetic subjects. Whether the insulin resistance syndrome is also related to arterial stiffness in non-diabetic subjects is less clear. We studied the association between variables of the insulin resistance syndrome in relation to arterial distensibility in healthy middle-aged non-diabetic women.

METHODS

This study was done in 180 non-diabetic women, aged 43-55, selected from the general population. Arterial distensibility was assessed in the carotid artery. The associations were evaluated using linear regression analyses.

RESULTS

Strong associations were found between arterial distensibility and the variables of the insulin resistance syndrome: body mass index, waist-to-hip ratio, high-density-lipoprotein-cholesterol, triglycerides, glucose, insulin, apolipoprotein A1, plasminogen activator inhibitor-1-antigen and tissue-type plasminogen activator-antigen. After additional adjustment for mean arterial pressure, common carotid arterial distensibility remained associated with body mass index: beta-coefficient (95% confidence interval) per kg/m2: -0.24 (-0.42; -0.06); waist-to-hip ratio: -26.62 (-40.59; -12.65) per m/m; triglycerides: -1.42(-2.77; -0.08) per mmol/l; plasminogen activator inhibitor-1-antigen: -0.01 (-0.02; -0.00) per ng/ml and borderline significant associated with high-density-lipoprotein-cholesterol: 1.93 (-0.01; 3.87; p = 0.07) per mmol/l. Clustering of variables of the insulin resistance syndrome was strongly related to decreased arterial distensibility which remained after adjustment for mean arterial pressure. No association was found between arterial distensibility and variables that are not part of the insulin resistance syndrome: total cholesterol, LDL-cholesterol and apolipoprotein B.

CONCLUSION/INTERPRETATION

The results of this study show that variables of the insulin resistance syndrome are associated with decreased arterial distensibility of the common carotid artery in healthy non-diabetic subjects.

Carotid atherosclerosis and cerebral white matter lesions in a population based magnetic resonance imaging study

Cerebral white matter lesions are frequently observed on magnetic resonance imaging of elderly, nondemented persons. There is evidence that white matter lesions are involved in the pathophysiology of cognitive decline and dementia. White matter lesions can be divided into those in the periventricular and those in the subcortical region. Pathological and epidemiological studies suggest that atherosclerosis is involved in the pathogenesis of these lesions. Our study reports on the association between atherosclerosis in the carotid arteries and white matter lesions in a population-based study among 1077 elderly subjects. We randomly sampled 1077 subjects aged between 60-90 years from two prospective population-based studies. All subjects underwent ultrasonography of the carotid artery. In addition, 1.5 T magnetic resonance imaging was performed; white matter lesions in the subcortical and periventricular regions were rated separately. With increasing number of plaques in the carotid artery the severity of periventricular white matter lesions increased (Ptrend = 0.03), but not the severity of subcortical white matter lesions (Ptrend = 0.19). In addition, an increase in intima media thickness was borderline significantly associated with an increased severity of periventricular white matter lesions (Ptrend = 0.09), but not of subcortical white matter lesions (Ptrend = 0.68). These findings suggest that partly dissimilar pathogenetic mechanisms are involved in the etiology of periventricular and subcortical white matter lesions.

Increased plasma homocysteine after menopause

Besides genetic defects in the enzymes involved in homocysteine metabolism and nutritional deficiencies in vitamin cofactors, sex steroid hormones may modulate plasma homocysteine levels. The post-menopausal state has been found to be associated with higher plasma homocysteine levels, but data are inconsistent and studies published so far did not adjust for age, which is an important confounding factor in studying the effect of menopause. In the present study total plasma homocysteine levels were measured in a meticulously selected population in which the contrast in estrogen status between pre- and postmenopausal women of the same age was maximized. The study comprised 93 premenopausal and 93 postmenopausal women of similar age (range 43-55 years). Women were selected from respondents to a mailed questionnaire on menopause, which was sent to all women aged 40-60 years in the Dutch town of Zoetermeer (n = 12675). Postmenopausal women who were at least three years after menopause or whose menses had stopped naturally before age 48 were age-matched with premenopausal women with regular menses and without menopausal complaints. Plasma homocysteine levels in the fasting state were related to menopausal status; the age-adjusted geometric mean was 10.7 micromol/l in premenopausal and 11.5 micromol/l in postmenopausal women (difference of 7%, 95% confidence interval 0.3-14%, P = 0.04). Additional adjustment for plasma creatinine, body mass index, smoking habit (yes, no) and alcohol intake did not influence this difference. The results of this population-based study indicate that plasma homocysteine is affected by menopause.

Prevalence, treatment, and control of hypertension by sociodemographic factors among the Dutch elderly

The study objective was to assess the prevalence, level of treatment, and control of hypertension in a general elderly population according to age and sociodemographic factors. We conducted a cross-sectional analysis of 7983 participants of the Rotterdam Study who were >/=55 years old and living in a district of Rotterdam. The prevalence of hypertension was based on blood pressure levels (>/=160/95 mm Hg) and the use of blood pressure-lowering medication for the indication of hypertension, type of treatment, and control of hypertension. Systolic blood pressure rises with age, whereas diastolic blood pressure declines. The prevalence of hypertension increases with age and was higher among women (39%) than among men (31%). About 80% of the hypertensives were aware of having hypertension, and 82% of the 80% were treated. For 70% of them, treatment was adequate with reference to conservative criteria. Hypertension was more prevalent among persons not living in a home for the elderly, for more-educated men, and for less-educated women. Persons without a partner and men living in a home for the elderly had a higher risk of being unaware of or of not being treated for existing hypertension. Treatment was more often successful among those living in a home for the elderly. The prevalence of hypertension was higher among older women and increased with age in both genders. A large proportion of hypertensive elderly persons were aware and were successfully treated for hypertension. The degree of awareness and control appeared to be affected by sociodemographic factors. More importantly, the majority of hypertensives did not have their hypertension well controlled. This group requires more attention by medical practitioners to reduce the burden of cardiovascular diseases in elderly persons.

Subclinical hypothyroidism is an independent risk factor for atherosclerosis and myocardial infarction in elderly women: the Rotterdam Study

BACKGROUND

Overt hypothyroidism has been found to be associated with cardiovascular disease. Whether subclinical hypothyroidism and thyroid autoimmunity are also risk factors for cardiovascular disease is controversial.

OBJECTIVE

To investigate whether subclinical hypothyroidism and thyroid autoimmunity are associated with aortic atherosclerosis and myocardial infarction in postmenopausal women.

DESIGN

Population-based cross-sectional study.

SETTING

A district of Rotterdam, The Netherlands.

PARTICIPANTS

Random sample of 1149 women (mean age +/- SD, 69.0 +/- 7.5 years) participating in the Rotterdam Study.

MEASUREMENTS

Data on thyroid status, aortic atherosclerosis, and history of myocardial infarction were obtained at baseline. Subclinical hypothyroidism was defined as an elevated thyroid-stimulating hormone level (>4.0 mU/L) and a normal serum free thyroxine level (11 to 25 pmol/L [0.9 to 1.9 ng/dL]). In tests for antibodies to thyroid peroxidase, a serum level greater than 10 IU/mL was considered a positive result.

RESULTS

Subclinical hypothyroidism was present in 10.8% of participants and was associated with a greater age-adjusted prevalence of aortic atherosclerosis (odds ratio, 1.7 [95% CI, 1.1 to 2.6]) and myocardial infarction (odds ratio, 2.3 [CI, 1.3 to 4.0]). Additional adjustment for body mass index, total and high-density lipoprotein cholesterol level, blood pressure, and smoking status, as well as exclusion of women who took beta-blockers, did not affect these estimates. Associations were slightly stronger in women who had subclinical hypothyroidism and antibodies to thyroid peroxidase (odds ratio for aortic atherosclerosis, 1.9 [CI, 1.1 to 3.6]; odds ratio for myocardial infarction, 3.1 [CI, 1.5 to 6.3]). No association was found between thyroid autoimmunity itself and cardiovascular disease. The population attributable risk percentage for subclinical hypothyroidism associated with myocardial infarction was within the range of that for known major risk factors for cardiovascular disease.

CONCLUSION

Subclinical hypothyroidism is a strong indicator of risk for atherosclerosis and myocardial infarction in elderly women.

Aortic atherosclerosis at middle age predicts cerebral white matter lesions in the elderly

BACKGROUND AND PURPOSE

MRI scans of the brains of elderly people frequently show white matter lesions. Clinically, these lesions are associated with cognitive impairment and dementia. A relation between atherosclerosis and white matter lesions was found in some small cross-sectional studies. However, atherosclerosis is a gradual process that starts early in life. We investigated the longitudinal association between aortic atherosclerosis assessed during midlife and late life and cerebral white matter lesions.

METHODS

We randomly sampled subjects between 60 and 90 years old from 2 population-based follow-up studies in which subjects had their baseline examinations in 1975 to 1978 (midlife) and in 1990 to 1993 (late life). In 1995 to 1996, subjects underwent 1.5-T MRI scanning; white matter lesions were rated in the deep subcortical and periventricular regions separately. Aortic atherosclerosis was assessed on abdominal radiographs that were obtained from 276 subjects in midlife and 531 subjects in late life.

RESULTS

The presence of aortic atherosclerosis during midlife was significantly associated with the presence of periventricular white matter lesions approximately 20 years later (adjusted relative risk, 2.4; 95% CI, 1.2 to 5.0); the relative risks increased linearly with the severity of aortic atherosclerosis. No association was found between midlife aortic atherosclerosis and subcortical white matter lesions (adjusted relative risk, 1.1; 95% CI, 0.5 to 2.3) or between late-life aortic atherosclerosis and white matter lesions.

CONCLUSIONS

The pathogenetic process that leads to cerebral periventricular white matter lesions starts already in or before midlife. The critical period for intervention directed at prevention of white matter lesions and its cognitive consequences may be long before these lesions become clinically detectable.

Education and nutrient intake in Dutch elderly people. The Rotterdam Study

OBJECTIVE

Unfavourable dietary habits might explain a part of the increased cardiovascular morbidity and mortality among the lower socioeconomic groups. The aim of the study was to describe differences in dietary intake in older subjects by socioeconomic status, as indicated by educational level.

DESIGN

A cross-sectional analysis of socioeconomic status in relation to dietary intake.

SETTING

The Rotterdam Study.

SUBJECTS

2213 men and 3193 women, aged 55 y and over living between 1990 and 1993 in a district of Rotterdam, The Netherlands.

METHODS

Dietary data were assessed with a semiquantitative food frequency questionnaire, containing 170 food items in 13 food groups.

RESULTS

In general, the dietary differences between socioeconomic groups were small. Lower educated subjects had a higher intake of almost all macronutrients compared with higher educated subjects. The total energy intake of men/women with the lowest educational level differed from those with the highest education in the following respect: 9.60/7.54 vs 8.94/7.17 MJ/day. Furthermore, fat composition was more adverse in the lower educated strata; in lower educated subjects, relatively more energy was derived from saturated fat (14.5/14.6 vs 13.8/13.8 energy%), the ratio of polyunsaturated saturated fat was lower (for men: 0.50 vs 0. 55) and the intake of cholesterol higher (271/220 vs 240/204 mg/day). These differences could be explained by a higher intake of visible fat (46/37 vs 44/34 g/day) and more meat consumption (130/100 vs 116/86 g/day). In addition, the composition of these products differed: the higher educated used relatively more lean meat and low-fat milk products. Furthermore, the intake of fibre was lower among the lower educated (1.88/2.17 vs 2.03/2.29 g/MJ). Among lower educated groups there were more abstainers (15.5/31.5 vs 12.3/26.9%) and the type of alcoholic beverages also differed between the groups. Intake of antioxidant vitamins from food alone did not differ between educational groups.

CONCLUSIONS

In Dutch elderly people, there are socioeconomic differences in dietary intake. Although these differences are small, these findings support the role of diet in the explanation of socioeconomic inequalities in cardiovascular health.

SPONSORSHIP

Erasmus Centre for Research on Aging, Erasmus University Rotterdam. European Journal of Clinical Nutrition (2000) 54, 159-165

Serum carotenoids and atherosclerosis. The Rotterdam Study

High circulating levels of carotenoids have been thought to exhibit a protective function in the development of atherosclerosis. We investigated whether aortic atherosclerosis was associated with lower levels of the major serum carotenoids in alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene, and zeaxanthin-in a subsample of the elderly population of the Rotterdam Study. Aortic atherosclerosis was assessed by presence of calcified plaques of the abdominal aorta. The case-control analysis comprised 108 subjects with aortic atherosclerosis and controls. In an age- and sex-adjusted logistic regression model, serum lycopene was inversely associated with the risk of atherosclerosis. The odds ratio for the highest compared to the lowest quartile of serum lycopene was 0.55 (95% CI 0.25-1.22; p(trend)=0.13). Multivariate adjustment did not appreciably alter these results. Stratification by smoking status indicated that the inverse association between lycopene and aortic calcification was most evident in current and former smokers (OR=0.35; 95% CI 0.13-0.94; p(trend)=0.04). No association with atherosclerosis was observed for quartiles of serum concentrations of alpha-carotene, beta-carotene, lutein, and zeaxanthin. In conclusion, this study provides evidence for a modest inverse association between levels of serum lycopene and presence of atherosclerosis, the association being most pronounced in current and former smokers. Our findings suggest that lycopene may play a protective role in the development of atherosclerosis.

A follow-up study of blood pressure and cerebral white matter lesions

White matter lesions are often observed on cerebral magnetic resonance imaging scans of elderly people and may play a role in the pathogenesis of dementia. Cross-sectional studies have shown an association between elevated blood pressure and white matter lesions. We prospectively studied the relation between blood pressure and white matter lesions in 1,077 subjects aged 60 to 90 years who were randomly sampled from two prospective population-based studies. One study had blood pressure measurements 20 years before, the other 5 years before. Overall response for the magnetic resonance imaging study was 63%, and declined from 73% among 60- to 70-year-olds to 48% for 80- to 90-year-olds. Diastolic and systolic blood pressure levels assessed 20 years before were significantly associated with subcortical and periventricular white matter lesions. The association between 20-year change in diastolic blood pressure and subcortical white matter lesions was J-shaped (relative risk, 2.2; 95% confidence interval, 1.0-5.2; and relative risk, 3.2; 95% confidence interval, 1.4-7.4, for decrease or increase of more than 10 mm Hg, respectively). The association between concurrent diastolic blood pressure level and white matter lesions was linear in subjects without, and J-shaped in subjects with, a history of myocardial infarction. Our results indicate that the J-shape relationship of diastolic blood pressure is not restricted to cardiovascular disease, but is also manifest in cerebrovascular disease.

Estrogen use and early onset Alzheimer's disease: a population-based study

Estrogen use may be protective for Alzheimer's disease with late onset. However, the effects on early onset Alzheimer's disease are unclear. This issue was studied in a population based setting. For each female patient, a female control was matched on age (within 5 years) and place of residence. Information on estrogen use and other risk factors were, for cases (n=109) and controls (n=119), collected from the next of kin by structured interview. The strength of the association between estrogen use and early onset Alzheimer's disease was studied using conditional logistic regression with adjustment for age and education level. There was an inverse association between estrogen use and early onset Alzheimer's disease (adjusted odds ratio 0.34; 95% confidence interval 0.12-0.94). The study therefore suggests that estrogen use is beneficial to Alzheimer's disease with early onset.

Hormone replacement therapy and intima-media thickness of the common carotid artery: the Rotterdam study

BACKGROUND AND PURPOSE

Observational data suggest that hormone replacement therapy (HRT) reduces morbidity and mortality from cardiovascular disease in healthy postmenopausal women. The mechanisms underlying this protection are not entirely clear but may include inhibition of the atherosclerotic process.

METHODS

We studied the association between ever use of HRT and intima-media thickness (IMT) of the common carotid artery in 1103 naturally menopausal women, aged 55 to 80 years, in the Rotterdam Study, a community-based cohort study in a suburban area of Rotterdam, Netherlands. Mean and maximum IMT of the common carotid artery were measured noninvasively with B-mode ultrasound.

RESULTS

Ever use of HRT for >/=1 year was associated with a decreased mean and maximum IMT compared with never users (mean IMT, 0.719 mm [SE 0.01] versus 0. 742 mm [SE 0.004], P=0.03; maximum IMT, 0.952 mm [SE 0.015] versus 0. 983 mm [SE 0.006], P=0.04), after adjustment for age, smoking, educational level, systolic blood pressure, and body mass index. No association was found for use <1 year (mean IMT, 0.739 mm [SE 0.013] versus 0.742 mm [SE 0.004], P=0.69; maximum IMT, 0.990 mm [SE 0.019] versus 0.983 mm [SE 0.006], P=0.75). Additional adjustment for diabetes, frequency of visits to healthcare facilities, or total and HDL cholesterol did not change these results.

CONCLUSIONS

The findings of this population-based study show that ever use of HRT is associated with a decreased IMT in the common carotid artery in elderly women.

J-shaped relation between blood pressure and stroke in treated hypertensives

The objective of this study was to investigate the relationship between hypertension and risk of stroke in the elderly. The study was performed within the framework of the Rotterdam Study, a prospective population-based cohort study. The risk of first-ever stroke was associated with hypertension (relative risk, 1.6; 95% CI, 1.2 to 2.0) and with isolated systolic hypertension (relative risk, 1.7; 95% CI, 1.1 to 2.6). We found a continuous increase in stroke incidence with increasing blood pressure in nontreated subjects. In treated subjects, we found a J-shaped relation between blood pressure and the risk of stroke. In the lowest category of diastolic blood pressure, the increase of stroke risk was statistically significant compared with the reference category. Hypertension and isolated systolic hypertension are strong risk factors for stroke in the elderly. The increased stroke risk in the lowest stratum of blood pressure in treated hypertensive patients may indicate that the therapeutic goal of "the lower the better" is not the optimal strategy in the elderly.

Menopausal status and risk factors for cardiovascular disease

OBJECTIVES

Changes in cardiovascular risk factors with menopausal status are difficult to study, owing to the high correlation of menopausal status with age. Therefore we examined cardiovascular risk factors in a meticulously selected population in which the contrast in oestrogen status between pre- and postmenopausal women of the same age was maximized.

DESIGN

Risk factors were compared in 93 premenopausal and 93 postmenopausal women who were matched on age (range 43-55 years).

SETTING

The women were selected from respondents to a mailed questionnaire about the menopause, which was sent to all women aged 40-60 years in the Dutch town of Zoetermeer (n = 12 675; response 54%).

SUBJECTS

Postmenopausal women who were at least 3 years after menopause or whose menses had stopped naturally before age 48 were age-matched with premenopausal women with regular menses and without menopausal complaints.

RESULTS

Compared to premenopausal women, postmenopausal women had significantly increased levels of total cholesterol (10.0%, 95% confidence interval 5.1-14.0), low density lipoprotein (LDL) cholesterol (14.0%, 6.9-19.9), and apolipoprotein B (8.2%, 0.6-15.5). The difference was present within 3 years after onset of menopause and did not show a trend towards an increase with the number of postmenopausal years. No differences were found in high density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1, blood glucose, insulin, body mass index, waist-to-hip ratio, and systolic and diastolic blood pressure.

CONCLUSIONS

The results of this study add to the evidence that total cholesterol, LDL cholesterol and apolipoprotein B are the primary cardiovascular risk factors affected by menopause.

The effect of APOE on dementia is not through atherosclerosis: the Rotterdam Study

The APOE genotype is involved in atherosclerosis, and atherosclerosis increases the risk of dementia, in particular among carriers of the APOE-epsilon4 allele. We studied, in a population-based setting (244 dementia cases; 1,002 nondemented controls), whether APOE is associated with dementia through atherosclerosis. As neither adjusting nor stratification for atherosclerosis altered the association of APOE with dementia, our study suggests that atherosclerosis is not an intermediate factor.

Tea flavonoids may protect against atherosclerosis: the Rotterdam Study

BACKGROUND

Epidemiological studies have indicated a protective role of dietary flavonoids in cardiovascular disease, but evidence is still conflicting. Tea is the major dietary source for flavonoids in Western populations. We studied the association of tea intake with aortic atherosclerosis in a general population.

METHODS

The present analysis formed part of the Rotterdam Study, a prospective study of men and women 55 years and older. Dietary intakes were assessed at baseline by a trained dietician who used a semiquantitative food frequency questionnaire. Calcified plaques in the abdominal aorta were radiographically detected after 2 to 3 years of follow-up. Aortic atherosclerosis was classified as "mild," "moderate," or "severe," according to the length of the calcified area (<1 cm, 1-5 cm, and >5 cm, respectively). The association of tea intake with severity of aortic atherosclerosis was studied in 3454 subjects who were free of cardiovascular disease at baseline. Data were analyzed by logistic regression, adjusting for age, sex, body mass index (calculated as weight in kilograms divided by the square of height in meters), smoking, education, and intake of alcohol, coffee, vitamin antioxidants, total fat, and total energy.

RESULTS

Multivariable analyses showed a significant, inverse association of tea intake with severe aortic atherosclerosis. Odds ratios decreased from 0.54 (95% confidence interval [CI], 0.32-0.92) for drinking 125 to 250 mL (1-2 cups) of tea to 0.31 (CI, 0.16-0.59) for drinking more than 500 mL/d (4 cups per day). The associations were stronger in women than in men. The association of tea intake with mild and moderate atherosclerosis was not statistically significant.

CONCLUSION

This study indicates a protective effect of tea drinking against ischemic heart disease.

Blood pressure and risk of myocardial infarction in elderly men and women: the Rotterdam study

OBJECTIVE

To study the association between blood pressure and risk of myocardial infarction in elderly subjects.

DESIGN

Prospective cohort study.

SETTING

The Rotterdam Study, a Dutch population-based study.

PARTICIPANTS

6004 men and women aged > or = 55 years.

MAIN OUTCOME MEASURES

Fatal or non-fatal myocardial infarction (n = 190) during a 4-year follow-up.

RESULTS

After excluding participants using blood pressure-lowering medication and participants with a history of myocardial infarction, increasing levels of systolic blood pressure (SBP) were associated with increasing risk of first myocardial infarction (P for trend < 0.0001). The relative risk (RR) for an SBP of 160 mmHg or higher was 5.7 (95% confidence interval (CI) 1.9-17.1) compared with an SBP below 120 mmHg. Increasing diastolic blood pressure (DBP) was also associated with increasing risk of first myocardial infarction, with the RR reaching 2.5 (95% CI 1.4-4.5) in subjects with values of 80-90 mmHg compared with values below 70 mmHg (P for trend < 0.05). Analyses in subjects aged 70 years and over showed that the positive associations between SBP and DBP and risk of first myocardial infarction remained at older age.

CONCLUSION

These findings in a relatively healthy cohort of elderly subjects do not provide evidence for a J- or U-shaped relation between SBP and DBP and risk of first myocardial infarction. They suggest that the risk of first myocardial infarction increases with increasing level of systolic and diastolic blood pressure and that this relationship persists into older age.

Hormone replacement therapy in perimenopausal women and 2-year change of carotid intima-media thickness

OBJECTIVES

To assess the 2-year effects of a combined regimen of oral 17beta-estradiol and desogestrel (17betaE-D) and a sequential combination of conjugated equine estrogens and norgestrel (CEE-N) on common carotid intima-media thickness and end-diastolic lumen diameter in comparison to placebo in perimenopausal women.

METHODS

The study was a single center, randomized, group-comparative, double-blind study with respect to the 17betaE-D and placebo groups and open with respect to CEE-N. After cycle 6, the blind was broken and the trial was continued as an open trial for another 18 months for the active study arms. The study included 121 perimenopausal women recruited from the general population. Common carotid intima-media thickness and end-diastolic lumen diameter were measured at baseline and cycle 24 with B-mode ultrasonography.

RESULTS

At cycle 24 small changes in intima-media thickness and lumen diameter were observed. Relative to placebo, changes in intima-media thickness were -0.009 mm [95% CI -0.045; 0.027] for 17betaE-D and -0.016 mm [95% CI -0.055; 0.024] for CEE-N. For end-diastolic lumen diameter the changes were -0.091 mm [95% CI -0.236; 0.055] and -0.125 mm [95% CI -0.820; 0.032] for 17betaE-D and CEE-N, respectively.

CONCLUSIONS

In this study among perimenopausal women a significant effect of 17betaE-D and CEE-N on common carotid intima-media thickness and lumen diameter could not be demonstrated. Although the sample size of the present trial is too limited to provide definite conclusions, the direction of the effect is in agreement with evidence from earlier studies on the effects of hormone replacement therapy in postmenopausal women.

Associations of C-reactive protein with measures of obesity, insulin resistance, and subclinical atherosclerosis in healthy, middle-aged women

Obesity, the insulin resistance syndrome, and atherosclerosis are closely linked and may all be determinants of an increased acute-phase response. In this study, we examined the relationship of C-reactive protein (CRP) with measures of obesity, variables of the insulin resistance syndrome, and intima-media thickness of the common carotid arteries in 186 healthy, middle-aged women selected from the general population. Associations were assessed by regression analysis. CRP was strongly associated with body mass index (BMI) and waist circumference. CRP was also associated with other variables of the insulin resistance syndrome, including blood pressure, insulin, high density lipoprotein cholesterol, triglycerides, apolipoprotein A1 (inversely), plasminogen activator inhibitor-1 antigen, and tissue-type plasminogen activator antigen. Associations between CRP and the variables of the insulin resistance syndrome disappeared after controlling for BMI but remained significant for plasminogen activator inhibitor-1 antigen only. The association of CRP with common carotid artery intima-media thickness was weak and limited to ever-smokers. BMI explained 29.7% of the variance of CRP, whereas common carotid artery intima-media thickness explained only 3.7%. The results of this population-based study indicate that adiposity is strongly associated with CRP in healthy, middle-aged women. In this population, BMI accounted for the relationship between CRP and other variables of the insulin resistance syndrome. Further studies should determine whether losing weight ameliorates the inflammatory state.

Socioeconomic status and aortic atherosclerosis in Dutch elderly people: the Rotterdam Study

An inverse association has been reported between socioeconomic status (SES) and cardiovascular morbidity and mortality. Studies on subclinical manifestations of atherosclerotic disease are limited and have not been carried out among elderly persons. The authors investigated the relation between SES and aortic atherosclerosis among elderly people. As part of the Rotterdam Study, data on SES and atherosclerosis were collected for 4,451 persons aged 55-94 years. Atherosclerosis was estimated by radiographic assessment of calcified deposits in the abdominal aorta. Aortic atherosclerosis was more common among women in the lower educational and occupational strata. The lowest educational group and the lowest occupational group had increased risks of aortic atherosclerosis compared with the highest groups (odds ratios were 1.3 (95% confidence interval (CI) 1.0-1.6) and 1.3 (95% CI 1.0-1.8), respectively). The odds ratios for severe atherosclerosis among women in the lowest socioeconomic stratum compared with those in the highest stratum were 1.6 (95% CI 1.0-2.7) for education, 2.8 (95% CI 1.1-7.5) for occupation, and 1.7 (95% CI 0.9-3.3) for income. After exclusion of persons with a history of cardiovascular disease, the same trends still emerged. No relations were observed among men. These findings show that SES is related to aortic atherosclerosis in women. This suggests that SES affects the incidence of cardiovascular disease before its clinical manifestation.

Serum cholesterol is a risk factor for myocardial infarction in elderly men and women: the Rotterdam Study

OBJECTIVE

To investigate the associations of serum total and HDL cholesterol with the risk of myocardial infarction in men and women of 55 years and over.

DESIGN

The Rotterdam Study is a population-based prospective cohort study. In total 2453 men and 3553 women of 55 years and older were included in this study. The mean duration of follow-up was 4 years.

MAIN OUTCOME MEASURES

Relative risks were estimated with Cox's proportional-hazard analysis. Cholesterol was analysed as a continuous variable and in sex-specific quartiles.

RESULTS

In subjects aged 55 years and older the relative risk of myocardial infarction was 1.9 in men (95% confidence interval 1.1-3.3) and 3.2 in women (1.5-6.4) in the highest compared to the lowest serum total cholesterol quartile (Q4 vs. Q1). In men and women of 70 years and older, total cholesterol remained an important risk factor for myocardial infarction (Q4 vs. Q1 relative risk 3.2; 1.3-7.7 and 2.9; 1.3-6.6, respectively). For HDL cholesterol, the relative risk in the highest compared to the lowest quartile (Q4 vs. Q1) was 0.5 in men (0.3-0.9) and 0.4 in women (0.2-0.9). HDL cholesterol was a weaker predictor in men after the age of 70 (Q4 vs. Q1 0.8; 0.3-2.1). In women of 70 years and older the relative risk was also not significant (Q4 vs. Q1 0.6; 0.3-1.3), although the trend over the quartiles was still significant.

CONCLUSION

Serum total cholesterol remains an important risk factor for myocardial infarction in men and women aged 70 years and older, whilst HDL cholesterol at older age remains important in women only.

Serum ferritin and risk of myocardial infarction in the elderly: the Rotterdam Study

BACKGROUND

Elevated body iron stores have been suggested to be a risk factor for ischemic heart disease.

OBJECTIVE

We examined whether elevated serum ferritin concentrations, other indicators of iron status, and dietary iron affected the incidence of myocardial infarction (MI) in an elderly population.

DESIGN

A nested, case-control study of 60 patients who had their first MI and 112 age- and sex-matched control subjects embedded in the population-based cohort of the Rotterdam Study.

RESULTS

The age- and sex-adjusted risk of MI for subjects with serum ferritin concentrations > or = 200 microg/L was 1.82 (95% CI: 0.90, 3.69; P = 0.096). The odds ratio (OR) was 1.26 (95% CI: 0.98, 1.64; P = 0.078) for the highest tertile of serum ferritin and was only slightly altered in a multivariate model. Risk of MI associated with the highest tertile of ferritin was most evident in current or former smokers (OR: 1.68; 95% CI: 1.17, 2.47; P for trend = 0.008) and in subjects with hypercholesterolemia (OR: 1.43; 95% CI: 0.99, 2.11; P for trend = 0.056) or diabetes (OR: 2.41; 95% CI: 1.12, 7.67; P for trend = 0.027). No association with risk of MI was observed for tertiles of serum iron, serum transferrin, or total dietary iron. For dietary heme iron, risk of MI was significantly increased in a multivariate model in which dietary energy, fat, saturated fat, and cholesterol were adjusted for (OR: 4.01; 95% CI: 1.17, 15.87; P for trend = 0.031).

CONCLUSION

In the presence of other risk factors, serum ferritin may adversely affect ischemic heart disease risk in the elderly.

Enhanced blood pressure response to mild sodium reduction in subjects with the 235T variant of the angiotensinogen gene

The relationship of high salt intake to elevated blood pressure levels has been demonstrated in most populations by cross-sectional, longitudinal, physiological, and clinical intervention studies. Variation within the angiotensinogen gene has been implicated in the genetic control of blood pressure levels and has been suggested to contribute to increased salt sensitivity. A total of 86 hypertensive men and women who had never been treated and who had participated in a 6-month randomized, placebo-controlled, clinical trial of low-sodium mineral salt (19% reduction in urinary sodium versus 12% increase in placebo group) were genotyped at the angiotensinogen M235T locus to test the hypothesis that the 235T allele is associated with a significant blood pressure response to a sodium reduction intervention whereas the 235M allele is not. After adjustment for gender and baseline blood pressure, persons with the TT and MT genotypes showed significant systolic blood pressure reductions on mineral salt compared with control subjects (P = .02 and P = .001, respectively) but not persons with the MM genotype (P = .10). Net adjusted diastolic blood pressure reductions also showed greater significance for persons with the TT and MT genotypes than for persons with the MM genotype (P = .08, P = .01, and P = .83, respectively). The net adjusted systolic and diastolic blood pressure reduction was -8.6/-3.9 mm Hg for persons with the TT genotype, -9.0/-5.2 mm Hg for the MT genotype, and -5.3/-1.0 mm Hg for the MM genotype. We conclude that the 235T allele of the angiotensinogen gene is associated with greater blood pressure decreases than the 235M allele after a sodium reduction intervention. The angiotensinogen gene accounts for some of the interindividual variation of the blood pressure response to sodium reduction.

Dietary iron and risk of myocardial infarction in the Rotterdam Study

Free iron has been implicated in lipid peroxidation and ischemic myocardial damage, and it has been suggested that iron is an independent risk factor for myocardial infarction. The authors investigated whether dietary iron is associated with an increased risk of fatal and nonfatal myocardial infarction in the Rotterdam Study, a community-based prospective cohort study of 7,983 elderly subjects in Rotterdam, the Netherlands. The study sample consisted of 4,802 participants who at baseline had no known history of myocardial infarction and for whom dietary data were available. From 1990 to 1996, 124 subjects had a myocardial infarction. No association was observed between total iron intake and risk of myocardial infarction after adjustment for age and sex (relative risk for the highest vs. the lowest tertile of intake = 0.89, 95% confidence interval (CI) 0.55-1.45, p for trend = 0.640). Heme iron intake was positively associated with risk of myocardial infarction (relative risk for the highest vs. the lowest tertile of intake = 1.83, 95% CI 1.16-2.91, p for trend = 0.008) after adjustment for age and sex, and this association persisted after multivariate adjustment (relative risk = 1.86, 95% CI 1.14-3.09, p for trend = 0.010). A distinction between fatal and nonfatal cases of myocardial infarction indicated that the association of heme iron with myocardial infarction was more pronounced in fatal cases. The results suggest that a high dietary heme iron intake is related to an increased risk of myocardial infarction and that it may specifically affect the rate of fatality from myocardial infarction.

Cross-sectionally assessed carotid intima-media thickness relates to long-term risk of stroke, coronary heart disease and death as estimated by available risk functions

OBJECTIVE

To relate cross-sectionally assessed indicators of carotid atherosclerosis measured in participants of the Rotterdam Study to absolute 10-12 year risks of stroke, coronary heart disease and death estimated by risk functions available from other studies.

SETTING

General population living in the suburb of Ommoord in Rotterdam, The Netherlands.

SUBJECTS

A sample of men and women (n = 1683), aged 55 years or over, drawn from participants from the Rotterdam Study (n = 7983).

MAIN OUTCOMES MEASURES

Three risk scores were used to estimate for each individual the absolute risk of stroke, coronary heart disease and death within 10-12 years as a function of their cardiovascular risk factor profile. Cross-sectionally measured indicators of carotid atherosclerosis (presence of atherosclerotic lesions and common carotid intima-media thickness) were subsequently related to these risk scores.

RESULTS

The 10-year absolute risk of stroke increased linearly from 4.8% (95% CI = 3.8, 5.8) for subjects in the lowest quintile to 16.1% (12.3, 21.9) for subjects in the highest quintile of common carotid intima-media thickness distribution. Similarly, the 10-year absolute risk for coronary heart disease rose from 13.1% (95% CI = 12.0, 14.2) to 23.4% (95% CI = 21.4, 25.4), whereas the risk of death within 11.5 years rose from 15.0% (95% CI = 12.8, 17.4) in the lowest quintile to 46.0% (42.8, 49.3) in the upper quintile. The absolute risks of stroke, coronary heart disease or death rose from 8.8, 15.8 and 26.9% to 14.3, 19.8 and 40.9%, respectively, when plaques in the common carotid artery were present. Similar findings were observed for plaques in the carotid bifurcation.

CONCLUSION

Common carotid intima-media thickness and carotid plaques are markers for increased risk of stroke, coronary heart disease and death within 10-12 years.

Menopausal status and distensibility of the common carotid artery

Although several studies have shown that exogenous estrogens have beneficial effects on arterial characteristics, the effect of endogenous estrogen on the vascular system is still unknown. In this study, distensibility, an indicator of arterial elasticity, of the common carotid artery was compared in pre- and postmenopausal women. The study comprised 93 premenopausal and 93 postmenopausal women of similar age (range, 43 to 55 years). Women were selected from respondents to a mailed questionnaire about the menopause, which was sent to all women aged 40 to 60 years in the Dutch town of Zoetermeer (n=12 675). Postmenopausal women who were at least 3 years past natural menopause or whose menses had stopped naturally before age 48, were age-matched with premenopausal women with regular menses and without menopausal complaints. The selection aimed at maximizing the contrast in estrogen status between pre- and postmenopausal women of the same age. Distensibility of the carotid artery was measured noninvasively with B-mode ultrasound and a vessel wall movement detector system. Arterial distensibility is expressed as the change in arterial diameter (distension, DeltaD) with the cardiac cycle, adjusted for lumen diameter, pulse pressure, and mean arterial blood pressure. Compared with premenopausal women, postmenopausal women had significantly lower arterial distension (DeltaD 370.5 microm [SE 9.5] versus 397.3 microm [SE 9.6]). These results suggest that the distensibility of the common carotid artery is negatively affected by natural menopause in presumed healthy women.

Dietary antioxidants and risk of myocardial infarction in the elderly: the Rotterdam Study

BACKGROUND

Epidemiologic studies have shown dietary antioxidants to be inversely correlated with ischemic heart disease.

OBJECTIVE

We investigated whether dietary beta-carotene, vitamin C, and vitamin E were related to the risk of myocardial infarction (MI) in an elderly population.

DESIGN

The study sample consisted of 4802 participants of the Rotterdam Study aged 55-95 y who were free of MI at baseline and for whom dietary data assessed by a semiquantitative food frequency questionnaire were available. During a 4-y follow-up period, 124 subjects had an MI. The association between energy-adjusted beta-carotene, vitamin C, and vitamin E intakes and risk of MI was examined by multivariate logistic regression.

RESULTS

Risk of MI for the highest compared with the lowest tertile of beta-carotene intake was 0.55 (95% CI: 0.34, 0.83; P for trend = 0.013), adjusted for age, sex, body mass index, pack-years, income, education, alcohol intake, energy-adjusted intakes of vitamin C and E, and use of antioxidative vitamin supplements. When beta-carotene intakes from supplements were considered, the inverse relation with risk of MI was slightly more pronounced. Stratification by smoking status indicated that the association was most evident in current and former smokers. No association with risk of MI was observed for dietary vitamin C and vitamin E.

CONCLUSION

The results of this observational study in the elderly population of the Rotterdam Study support the hypothesis that high dietary beta-carotene intakes may protect against cardiovascular disease. We did not observe an association between vitamin C or vitamin E and MI.

Performance of a predictive model to identify undiagnosed diabetes in a health care setting

OBJECTIVE

To develop a predictive model to identify individuals with an increased risk for undiagnosed diabetes, allowing for the availability of information within the health care system.

RESEARCH DESIGN AND METHODS

A sample of participants from the Rotterdam Study (n = 1,016), aged 55-75 years, not known to have diabetes completed a questionnaire on diabetes-related symptoms and risk factors and underwent a glucose tolerance test. Predictive models were developed using stepwise logistic regression analyses with the absence or presence of newly diagnosed diabetes as the dependent variable and various items with a plausible connection to diabetes as the independent variables. The models were evaluated in another Dutch population-based study, the Hoorn Study (n = 2,364), in which the participants were aged 50-74 years. Performances of the predictive models were compared by using receiver-operator characteristics (ROC) curves.

RESULTS

We developed three predictive models (PMs), PM1 contained information routinely collected by the general practitioner, while PM2 also contained variables obtainable by additional questions. The third predictive model, PM3, included variables that had to be obtained from a physical examination. These latter variables did not have additive predictive value, resulting in a PM3 similar to PM2. The area under the ROC curve was higher for PM2 than for PM1, but the 95% Cls overlapped (0.74 [0.70-0.78] and 0.68 [0.64-0.72], respectively).

CONCLUSIONS

Using only information normally present in the files of a general practitioner, a predictive model was developed that performed similarly to one supplemented by information obtained from additional questions. The simplicity of PM1 makes it easy to implement in the current health care setting.

Physical activity in elderly subjects with impaired glucose tolerance and newly diagnosed diabetes mellitus

The authors carried out a study to investigate the association between different indicators of physical activity and the prevalence of impaired glucose tolerance (IGT) and newly diagnosed diabetes (nDM) in a population-based cohort of elderly men and women in the Netherlands. A sample of participants of the Rotterdam Study (n = 1,016) aged 55-75 years who were not known to have diabetes mellitus underwent an oral glucose tolerance test. Physical activity was assessed by means of a self-administered questionnaire and expressed as time spent on activities per week. Associations with the prevalence of IGT and nDM were assessed by logistic regression analysis after adjustment for age, body mass index, waist-hip ratio, family history of diabetes, and smoking. A total of 745 subjects had normal glucose tolerance, 153 IGT, and 118 nDM. The total amount of time spent on physical activity decreased with increasing glucose intolerance. Adjusted for main confounders, vigorous activities such as bicycling (men: odds ratio (OR) = 0.26, 95% confidence interval (CI) 0.14-0.49; women: OR = 0.37, 95% CI 0.18-0.78) and sports (men: OR = 0.28, 95% CI 0.11-0.74) showed an inverse association with the presence of nDM. For IGT, the associations pointed in the same direction but did not reach statistical significance. These results indicate that physical inactivity and glucose intolerance are associated among older adults similar to the way they are associated among middle-aged adults.

Serum caeruloplasmin as a coronary risk factor in the elderly: the Rotterdam Study

Serum Cu and caeruloplasmin levels have been suggested to be independent risk factors for CHD operating through oxidative modification of LDL. However, given its function as an acute-phase protein, the question has been raised whether an elevated caeruloplasmin level is not merely an indicator of inflammation. In the current study, we investigated whether serum caeruloplasmin was associated with subsequent myocardial infarction, taking into account indices of inflammation. The study population consisted of 210 cases of first myocardial infarction and controls, frequency-matched on age (5-year categories) and sex, selected from the population-based cohort of the Rotterdam Study. Serum caeruloplasmin levels were significantly elevated in cases of myocardial infarction compared with controls (510 (SD 110) v. 470 (SD 100) mg/l; P = 0.007). Risk of myocardial infarction for the highest compared with the lowest quartile of caeruloplasmin was 2.46 (95% CI 1.04, 6.00; Ptrend = 0.043) after adjustment for age, sex, BMI, pack-years smoked, serum cholesterol, systolic blood pressure, and income. The relative risk was most evident in current smokers. Adjustment for C-reactive protein and leucocyte count reduced the excess risk by 33%. This suggests that a substantial part of the observed association between serum caeruloplasmin and CHD may be attributed to inflammation processes rather than to the pro-oxidant activity of caeruloplasmin.

Homocysteine and short-term risk of myocardial infarction and stroke in the elderly: the Rotterdam Study

BACKGROUND

Elevated homocysteine level increases vascular disease risk. Most data are based on subjects younger than 60 years; data for the elderly are more limited. We examined the relationship of homocysteine level to incident myocardial infarction and stroke among older subjects in a nested case-control study.

METHODS

Subjects were participants in the Rotterdam Study, a cohort study among 7983 subjects residing in the Ommoord district of Rotterdam, the Netherlands. Baseline examinations were performed from March 1, 1990, to July 31, 1993. The analysis is restricted to myocardial infarction and stroke that occurred before December 31, 1994. One hundred four patients with a myocardial infarction and 120 with a stroke were identified with complete data. Control subjects consisted of a sample of 533 subjects drawn from the study base, free of myocardial infarction and stroke. Nonfasting total homocysteine levels were measured.

RESULTS

Results were adjusted for age and sex. The risk of stroke and myocardial infarction increased directly with total homocysteine. The linear coefficient suggested a risk increase by 6% to 7% for every 1-micromol/L increase in total homocysteine. The risk by quintiles of total homocysteine level was significantly increased only in the group with levels above 18.6 micromol/L (upper quintile): odds ratios were 2.43 (95% confidence interval, 1.11-5.35) for myocardial infarction and 2.53 (95% confidence interval, 1.19-5.35) for stroke. Associations were more pronounced among those with hypertension.

CONCLUSIONS

The present study, based on a relatively short follow-up period, provides evidence that among elderly subjects an elevated homocysteine level is associated with an increased risk of cardiovascular disease.

G-estimation of causal effects: isolated systolic hypertension and cardiovascular death in the Framingham Heart Study

Time-dependent covariates are often both confounders and intermediate variables. In the presence of such covariates, standard approaches for adjustment for confounding are biased. The method of G-estimation allows for appropriate adjustment. Previous studies applying the G-estimation method have addressed effects on all-cause mortality rather than on specific causes of death. In the present study, a method to adjust for censoring by competing risks is presented. The authors used the approach to estimate the causal effect of isolated systolic hypertension on cardiovascular mortality in the Framingham Heart Study, with a 10-year follow-up using data from 1956 to 1970. Arterial rigidity is a major determinant of isolated systolic hypertension and may be a confounder of the relation between isolated systolic hypertension and cardiovascular death. Conversely, isolated systolic hypertension may by itself contribute to stiffening of the vessel wall, and arterial rigidity may therefore also be an intermediate variable in the causal pathway from isolated systolic hypertension to cardiovascular death. While controlling for arterial rigidity and other baseline and time-dependent covariates, isolated systolic hypertension decreased the time to cardiovascular death by 45% (95% confidence interval 3-69).

Dietary assessment in the elderly: validation of a semiquantitative food frequency questionnaire

OBJECTIVE

The study was conducted to assess the relative validity of a 170-item semiquantitative food frequency questionnaire (SFFQ) adapted for use in the elderly.

DESIGN AND SUBJECTS

The study was carried out in a sample of 80 men and women aged 55-75 y participating in a community based prospective cohort study in Rotterdam, The Netherlands. The two-step dietary assessment comprised a simple self-administered questionnaire (20 min) followed by a structured interview with trained dietitians (20 min) based on the completed questionnaire. Multiple food records (FR) collected over a one year period served as reference method. 24 h urine urea was used as indirect marker for protein intake.

RESULTS

Compared with FR, the SFFQ generally overestimated nutrient intake as reflected by difference in means and the ratio of SFFQ to FR. Energy adjustment reduced the observed overestimation. Pearson's correlation coefficients varied from close to 0.5 to about 0.9 for crude data, and after adjustment for age, sex, total energy intake, and for within-person variability in daily intake for 0.4-0.8. Cross-classification into quintiles resulted in correct classification into the same or adjacent quintile of 75.8% for crude and 76.8% for energy-adjusted data. Validation of protein intake estimated by SFFQ with protein excretion from 24h urine urea indicated overestimation of protein intake by SFFQ. Spearman correlation coefficient between protein intake estimated from urea excretion and SFFQ was 0.67.

CONCLUSIONS

Adaptation of a SFFQ for use in the elderly resulted in a valid and time-efficient dietary assessment instrument. Its ability to adequately rank study subjects according to their dietary intake support its application in epidemiological studies in the elderly.

Smoking and risk of dementia and Alzheimer's disease in a population-based cohort study: the Rotterdam Study

BACKGROUND

Previous studies suggested a protective effect of smoking on Alzheimer's disease, but most were case-control studies based on prevalent cases. The findings of prospective studies on the association between smoking and the risk of dementia are inconclusive.

METHODS

We did a population-based follow-up study of elderly people who were initially free of dementia. 6870 people aged 55 years and older agreed to take part. Smoking history was taken at baseline and participants were classified as never smokers, former smokers, and current smokers. During follow-up, we recorded all incident cases of dementia. We used never smokers as the reference category to calculate relative risks of dementia and Alzheimer's disease by Cox proportional hazards regression, after adjustment for age, sex, education, and alcohol intake. We also examined modification of risk by age, sex, and the apolipoprotein E (APOE) genotype.

FINDINGS

During mean follow-up of 2.1 (range 1.5-3.4) years, 146 incident cases of dementia were detected, of which 105 were Alzheimer's disease. Compared with never smokers, smokers had an increased risk of dementia (relative risk 2.2 [95% CI 1.3-3.6]) and Alzheimer's disease (2.3 [1.3-4.1]). Smoking was a strong risk factor for Alzheimer's disease in individuals without the APOEepsilon4 allele (4.6 [1.5-14.2]), but had no effect in participants with this allele (0.6 [0.1-4.8]).

INTERPRETATION

Smoking was associated with a doubling of the risk of dementia and Alzheimer's disease. Our finding that carriers of the APOEepsilon4 had no increased risk of dementia suggests an interaction between smoking and the APOEepsilon4 genotype in the aetiology of Alzheimer's disease.

[Association between the intima-media thickness of the common carotid and subsequent cardiovascular events in subjects, 55 years and older, in the Rotterdam study (ERGO)]

OBJECTIVE

To determine whether common carotid artery intima-media thickness (IMT) is related to future cardiovascular disease.

DESIGN

Nested case control study.

SETTING

The suburb of Ommoord in Rotterdam, the Netherlands.

METHOD

As part of the Rotterdam study among 7983 subjects aged 55 years and over, ultrasound images of the common carotid artery were stored on videotape of 5965 subjects at baseline (1990-1993). Analysis (logistic regression) was based on 190 cases of cardiovascular disease (myocardial infarction and stroke), registered up to December 31, 1994. IMT was measured from videotape for all cases and a control sample of 1373 subjects who remained free from myocardial infarction and stroke during follow-up. The mean duration of follow-up was 2.7 years.

RESULTS

The age and sex adjusted cardiovascular disease risk increased by 45% (95% confidence interval (95% CI): 25-69) per standard deviation increase (0.163 mm) in IMT. Stroke risk increased by 45% (95% CI: 25-69) per standard deviation increase and the risk of myocardial infarction increased by 43% (95% CI: 16-78). Additional adjustment for several cardiovascular risk factors attenuated the association.

CONCLUSION

Increased common carotid intima-media thickness was associated with subsequent cardiovascular events. These results support the use of carotid intima-media thickness measurements as a surrogate endpoint in observation and intervention studies. The value of IMT measurements for individual patients and cardiovascular screening merits further study.

Dietary effects on coagulation factor VII vary across genotypes of the R/Q353 polymorphism in elderly people

The objective of this study was to evaluate the association of factor VII with dietary factors while also considering the R/Q353 polymorphism. Nutrition is an important determinant of coagulation factor VII, which is also genetically determined by the R/Q353 polymorphism. High levels of coagulation factor VII clotting activity (FVII:C) are associated with the risk of myocardial infarction; nutrition may have an effect on these levels if people are genetically susceptible to dietary changes. FVII:C was measured in 3005 elderly subjects, and the extreme quintiles of the FVII:C distribution were selected for measurement of the R/Q353 genotype and FVII:Chr (reflects total factor VII). In these 1158 subjects, habitual diet was assessed with a semiquantitative food-frequency questionnaire. The frequency of the Q353 allele was 0.24 in the lowest and 0.09 in the highest quintile. The quintiles were combined for linear regression analyses. FVII:C was inversely associated with fiber [beta = -0.64 %pooled plasma (PP)/g, confidence interval (CI): -1.07,-0.21] and protein intake (beta = -0.16 %PP/g, CI: -0.31,-0. 01) and positively with saturated fat intake (beta = 0.19 %PP/g, CI: -0.10,0.48). FVII:Chr was inversely associated with fiber (beta = -0. 38 %PP/g, CI: -0.71,-0.05). No other associations with diet were observed. The inverse association of FVII:C with fiber was stronger in subjects with the RR genotype (beta = -0.76 %PP/g, CI: -1.23,-0. 29), than in those with the RQ/QQ genotypes (beta = -0.19 %PP/g, CI: -0.97,0.59). The same was found for FVII:Chr. The association of FVII:C with saturated fat was positive in those with the RR allele and inverse in those carrying the Q allele. These findings suggest that the strength of the association between coagulation factor VII and diet varies across the genotypes of the R/Q353 polymorphism.

Risk factors for increased bone loss in an elderly population: the Rotterdam Study

The association of bone loss with age, sex, and several prevalent and modifiable potential risk factors for osteoporosis was studied in 1,856 men and 2,452 women aged 55 years and over from the Rotterdam Study, a population-based cohort study in the Netherlands. The rate of change in femoral neck bone mineral density was estimated longitudinally between 1990 and 1995, after 2 years of follow-up on average. These rates, adjusted for age and body mass index, were -0.0025 (95% confidence interval -0.0038 to -0.0012) in men and -0.0045 (95% confidence interval -0.0056 to -0.0034) g/cm2/year in women (p=0.03). Bone loss accelerated with age, as seen more clearly in men than in women. Lower body mass index and cigarette smoking were associated with increased bone loss in both men and women. In men, higher calcium intake was associated with lower rates, and disability was associated with borderline significantly higher rates of bone loss (p=0.07). In women, a nonsignificant relation was observed with disability, but not with dietary calcium intake. Alcohol intake was not consistently related to the rate of bone loss in either sex. It is concluded that in elderly people the rate of bone loss is higher in women, progresses with age, and is further determined by several modifiable risk factors, particularly in men.

Dietary fat intake and the risk of incident dementia in the Rotterdam Study

A high intake of saturated fat and cholesterol and a low intake of polyunsaturated fatty acids have been related to an increased risk of cardiovascular disease. Cardiovascular disease has been associated with dementia. We investigated the association between fat intake and incident dementia among participants, age 55 years or older, from the population-based prospective Rotterdam Study. Food intake of 5,386 nondemented participants was assessed at baseline with a semiquantitative food-frequency questionnaire. At baseline and after an average of 2.1 years of follow-up, we screened for dementia with a three-step protocol that included a clinical examination. The risk of dementia at follow-up (RR [95% CI]) was assessed with logistic regression. After adjustment for age, sex, education, and energy intake, high intakes of the following nutrients were associated with an increased risk of dementia: total fat (RR = 2.4 [1.1-5.2]), saturated fat (RR = 1.9 [0.9-4.0]), and cholesterol (RR = 1.7 [0.9-3.2]). Dementia with a vascular component was most strongly related to total fat and saturated fat. Fish consumption, an important source of n-3 polyunsaturated fatty acids, was inversely related to incident dementia (RR = 0.4 [0.2-0.91), and in particular to Alzheimer's disease (RR = 0.3 [0.1-0.9]). This study suggests that a high saturated fat and cholesterol intake increases the risk of dementia, whereas fish consumption may decrease this risk.

Birth weight, growth, and blood pressure: an annual follow-up study of children aged 5 through 21 years

Associations between birth weight and blood pressure have been found in children and adults. In this longitudinal study, the objective was to assess the relation between birth weight and blood pressure level and the change in blood pressure from childhood and young adolescence into adulthood. A cohort of 483 children from a middle-class community in the town of Zoetermeer in the Netherlands had annual measurements of blood pressure during an average follow-up period of 14 years. For 330 of these participants, initially aged 5 through 21 years, birth weight data were collected, which were related to blood pressure level and blood pressure change. An inverse association between birth weight and systolic blood pressure was found, with adjustment for current body height and weight, sex, and use of alcohol, cigarettes, and oral contraceptives. This inverse association was found for the total follow-up in 5- to 37- year-olds (regression coefficient: -2.4 mm Hg/kg; 95% confidence interval: -3.9 to -1.0, as well as in most individual age groups: 5 through 9 years (-0.6 mm Hg/kg, -3.2 to 2.0); 10 through 14 years (-2.5 mm Hg/kg, -4.7 to -0.4); 15 through 19 years (-3.1 mm Hg/kg, -4.9 to -1.2); 20 through 24 years (-2.7 mm Hg/kg, -4.6 to -0.9); 25 through 29 years (-2.0 mm Hg/kg, -3.9 to -0.01); and 30 through 37 years (-1.9 mm Hg/kg, -4.6 to 0.7). For diastolic blood pressure, there appeared to be an inverse association with birth weight in the age group of 30 through 37 years, both unadjusted (-2.0 mm Hg/kg, -4.6 to 0.5) and adjusted for risk factors other than sex (-2.3 mm Hg/kg, -4.7 to 0.1), although these findings were of borderline statistical significance. The results were independent of gestational age and were similar in the group of subjects with low birth weight but normal gestational age (-2.7 mm Hg/kg, -4.3 to -1.0). In relation to systolic blood pressure, birth weight showed a significant interaction with body mass index (regression coefficient, 0.02; SE=0.01; P=.05). There was no relation between birth weight and change in systolic or diastolic blood pressure with age. Our longitudinal study shows that birth weight is consistently inversely associated with systolic blood pressure level from childhood to young adulthood and with diastolic blood pressure in young adulthood. Birth weight is not related to change of blood pressure with increasing age. Low birth weight in combination with high current body mass index seems to be of particular importance in the development of high blood pressure.

Electrolytes are associated with blood pressure at old age: the Rotterdam Study

We examined the association of urinary sodium and potassium excretion with blood pressure (BP) in the Rotterdam Study, a population-based study among 7983 men and women aged 55 and over. The present analysis included 1006 subjects with complete BP and urinary data who did not use antihypertensive drugs and did not report themselves to be hypertensive. Electrolyte excretions were assessed in a timed nocturnal urine sample and standardized to 24-h values. The association of electrolyte excretions with BP was studied in a multiple linear regression model with adjustment for age, sex, and body mass index. When sodium and potassium were entered simultaneously into the multivariate model, a 100 mmol increase in potassium was associated with a 9.4 decrease in systolic (P = 0.01) and a 4.9 mm Hg decrease in diastolic BP (P = 0.01). Sodium was directly related to BP, with a 2.2 mm Hg increase in systolic (P = 0.06) and a 0.8 mm Hg increase in diastolic BP (P = 0.14) per 100 mmol. Our findings suggest that an increased intake of potassium and a decrease intake of salt may lower BP at old age.