Ecology of Food and Nutrition

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Established and Suspected Biomarkers of Cardiovascular Disease (CVD) Risk in Pre-Menopausal Lebanese Women Omar Obeid a; Lynn Al Khatib a; Malek Batal a; Nada Adra a; Nahla Hwalla a a Department of Nutrition and Food Science, Faculty of Agricultural and Food Sciences, American University of Beirut, Lebanon Online Publication Date: 01 May 2008 To cite this Article: Obeid, Omar, Al Khatib, Lynn, Batal, Malek, Adra, Nada and Hwalla, Nahla (2008) 'Established and Suspected Biomarkers of Cardiovascular Disease (CVD) Risk in Pre-Menopausal Lebanese Women', Ecology of Food and Nutrition, 47:3, 298 — 311 To link to this article: DOI: 10.1080/03670240701821337 URL: http://dx.doi.org/10.1080/03670240701821337

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Ecology of Food and Nutrition, 47: 298–311, 2008 Copyright © Taylor & Francis Group, LLC ISSN: 0367-0244 print / 1543-5237 online DOI: 10.1080/03670240701821337

1543-5237 0367-0244 -GEFN Ecology of Food and Nutrition Nutrition, Vol. 47, No. 3, Apr 2008: pp. 0–0

ESTABLISHED AND SUSPECTED BIOMARKERS OF CARDIOVASCULAR DISEASE (CVD) RISK IN PRE-MENOPAUSAL LEBANESE WOMEN

Nutrition O. Obeid et of al. Pre-Menopausal Women

OMAR OBEID LYNN AL KHATIB MALEK BATAL NADA ADRA NAHLA HWALLA Department of Nutrition and Food Science, Faculty of Agricultural and Food Sciences, American University of Beirut, Lebanon

Cardiovascular disease (CVD) is known to be caused by both environmental and non-environmental factors and the contribution of these factors seems to vary among different populations. Major nutritional biomarkers of CVD in 290 Lebanese pre-menopausal women were assessed. Diabetes, folate, and vitamin B12 deficiencies were rare (below 0.5%) among the subjects. Abnormalities in lipid profile were more common, in which 16.7% of subjects had low HDL-cholesterol. Vitamin B6 deficiency was also present at 14.5%. Low levels of HDL (established biomarker) and vitamin B6 (suspected biomarker) seem to be the major nutritional abnormalities in Lebanese females of childbearing age. KEYWORDS Nutritional biomarkers, CVD, Homocysteine, folate, vitamin B6, vitamin B12

Address correspondence to Omar Obeid, Ph.D., Department of Nutrition and Food Science, American University of Beirut, P.O. Box 11-0236, Riad El Solh, Beirut 1107-2020, Lebanon. E-mail: [email protected] 298

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INTRODUCTION Cardiovascular disease (CVD) is a major global health problem that is reaching epidemic proportions in both developed and developing countries (Stangl and Baumann, 2002; Jafar, 2006). Every year, about 12 million people throughout the world die of either a heart attack or stroke (FAO/WHO, 2003). In industrialized countries, nearly one in every two deaths is attributed to CVD; cardiovascular mortality being prevalent for both women and men (Stangl and Baumann, 2002). The significance of total cholesterol as a predictor of CVD in women is evidently minimal (Kuulasmaa et al., 2000; Garber et al., 1996), while that of low HDL-C value (< 35mg/dl) is considered an independent atherogenic risk factor for women (Maron, 2000). Data from observational studies suggests that: independent of age, body mass index, smoking, LDL-C, and blood pressure, for every 1mg/dl increment of HDL-C, there is a 2% decrease risk of CVD in men and 3% decrease risk of CVD in women (Gordon et al., 1989). On the other hand, hypertriglyceridemia represents a greater risk factor for women as compared to men (Hokanson and Austin, 1996). In addition, diabetes in women was considered as one of the most powerful predictors of CVD and this was reported to exhibit a great disadvantage especially to pre-menopausal women (Laing et al., 1999; Iglseder et al., 2005). In comparison to the cardiovascular mortality of age- and gender-adjusted controls, the CAD risk of diabetic women was 7 times greater in the first two decades of life, 11·3 times greater in the third and fourth decades, and 7·8 times greater in the fifth and sixth decades. The respective factors for men were significantly lower: 3·9, 5·7, and 4·7 (Laing et al., 1999). The CVD risk for women rises systematically with BMI, up to a factor of 3·6 in women with BMI > 29 in comparison with BMI < 21 (Willett et al., 1995). Moreover, hyperhomocysteinemia has been identified as a risk factor for arterial damage since the 1960’s (McCully, 1969). Recent meta-analysis identified hyperhomocysteinemia as an independent predictor of CVD and stroke (Homocysteine Studies Collaboration, 2002; Wald et al., 2002) although the nature of the relationship is not clear as to whether it is causal or marker (Mangoni and Jackson, 2002). Elevated levels of plasma total homocysteine (tHcy) can be the result of both non-nutritional and nutritional factors; the latter includes folate, vitamin B6 and B12, all are involved in the metabolism of homocysteine (De Bree et al., 2002). Folic acid


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supplement (0.4–0.5 mg/d) was reported to reduce tHcy by 25% (Boushey et al., 1995) while a higher folic acid supplement (5mg/d) was found to improve endothelial function in CVD patients by a mechanism largely independent of homocysteine (Doshy et al., 2002). Addition of vitamin B12 and B6 above that of folate was reported to have a small THcy lowing (Homocysteine Studies Collaboration, 2002; Homocysteine Lowering Trialists’ Collaboration, 1998; McKinley et al., 2001). Moreover, vitamin B6 was shown to have a protective effect against coronary heart disease that was independent of both tHcy and cholesterol (Folsom et al., 1998). However, recent data showed that lowering tHcy by a combination of folate, B6 and B12 failed to reduce the risk of major cardiovascular events in patients with vascular disease (The Heart Outcome Prevention Evaluation [HOPE-2] investigators, 2006) and did not lower recurrent CVD after acute myocardial infarction (Bonaa et al., 2006) It is well know that incidences of CVD increase with age and is highest among women after menopause. Thus early detection of any abnormalities would be useful for the development of early protective actions. In addition, abnormalities in the nutritional status of the mother are know to have a long term effect on the nutritional status of the offspring. The present study was designed to assess the role of biochemical markers of nutritional status in the CVD risk factors of pre-menopausal women

METHODS Subjects Two hundred and ninety subjects were taken from a larger study involving 506 pre-menopausal women (aged 15–45 years) attending health centers across Lebanon. Women were randomly recruited from a random sample of 23 health centers operated by the Ministry of Social Affairs and distributed across the six districts (Muhafazats) of Lebanon. Families of low to moderate socio-economic status usually attend such centers. Pregnant and lactating women were excluded. The Institutional Review Board of the American University of Beirut approved the study protocol, and a written informed consent was obtained from all participants. Plasma levels of folate and vitamin B12 of the larger study were reported in a recent publication (Al Khatib et al., 2006).

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Data Collection Data collection took place between May and December 2003. Anthropometric indicators were obtained for all participants. The height was measured without shoes and recorded to the nearest 0.5cm. The weight was measured in light indoor clothing to the nearest 0.1 kg using a calibrated scale. A 10-ml venous blood sample was drawn from all subjects into a sterile EDTA tube for measurement of biochemical and other study parameters. Samples were taken early in the morning, after an 8 - 10 hour fast, by a registered nurse. Blood samples were immediately placed in an icebox, for a period not exceeding three hours, and were subsequently centrifuged and frozen for later analysis.

Blood and Laboratory Measurements Plasma lipids (triglycerides, low-density lipoproteins and high-density lipoproteins) and glucose were all analyzed by an enzymatic colorimetric method using the BM/Hitachi System 704/911. Vitamin B6 (pyridoxal 5phosphate, PLP) plasma values were measured using a radioenzymatic assay kit (Buhlmann, Buhlmann Laboratories, Schönenbuch, Switzerland). Plasma folate and vitamin B12 were analyzed using the AXSYM system (Abbott AXSYM System, Abbott Laboratories), while plasma homocysteine (for 220 subjects) was determined by HPLC (te PoelePothoff et al., 1995).

Cut off Values According to the American Diabetes Association (American Diabetes Association, 2007) a subject with fasting plasma glucose (FPG) ≥ 126 mg/dl was considered diabetic and an FPG between 100 and 125 mg/dl was classified as impaired fasting glucose (IFG). A total cholesterol level of 240 mg/dl was considered as high and values between 200 and 239 mg/dl as borderline high. Plasma levels of LDL-C ≥ 160 mg/dl and HDL-C ≥ 60 mg/dl were classified as high while ranges of 100–159 mg/dl and 40–59 mg/ dl were defined as borderline high for LDL-C and HDL-C respectively. As for triglycerides, 200 mg/dl was adopted as the cut off and values between 150 and 199 mg/dl were considered borderline high. A plasma homocysteine ≥ 26 μmol/l was considered high and values between 15 and 25 μmol/l


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were defined as marginal high. Concerning the B vitamins, deficient plasma vitamin B6 was defined as plasma levels below 30nM and marginal deficiency when they ranged between 30 and 60nM. Folate and vitamin B12, plasma levels 6): n (%)

Values in the same row with different superscripts are significantly different

a,b

Vitamin B12 (pg/ml) Deficient (< 150): n (%) Low (150–200): n (%) Normal (> 200): n (%)

26–35

15–25

Age Group

394.4 ± 207.20 0(0.0) 1(1.6) 63(98.4)

8.99 ± 2.76b 0(0.0) 5(7.9) 58(92.1)

70.9 ± 56.85ab 29(22.3) 44(33.8) 57(43.9)

9.4 ± 5.47 0(0) 10(20) 40(80)

36–45

401.6 ± 199.85 0(0.0) 3(1.1) 271(98.9)

8.4 ± 2.37 0(0.0) 31(11.4) 242(88.6)

68.9 ± 48.93 42(14.5) 114(39.4) 133(46.0)

9.6 ± 6.03 4(1.8) 37(16.9) 178(81.3)

Total

0.939

0.045

0.029

0.331

P

Table 2. Distribution of biochemical indices (plasma homocysteine, VitaminB6, folate and vitamin B12) of Lebanese women of childbearing age by age group



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μmol/L. Mean plasma vitamin B6 was 68.9 nM and that of the age group 26–35 was the lowest, this was in turn associated with a large percentage of marginal deficiency. However, the percentage of subjects with deficiency (