239
Atherosclerosis, 84 (1990) 239-244 Elsevier Scientific Publishers Ireland, Ltd.
ATHERO 04545
Influence of smoking, body fat distribution, and alcohol consumption on serum lipids, lipoproteins, and apolipoproteins in early postmenopausal women Jens Haarbo, Christian Hassager, Annette Schlemmer and Claus Christiansen Department of Clinical Chemistry, Glostrup Hospital, University of Copenhagen, DK-2600 Glostrup (Denmark) (Received 4 April, 1990) (Revised, received 22 June, 1990) (Accepted 29 June, 1990)
The impact of smoking, alcohol consumption, obesity, and body fat distribution (measured either directly by dual photon absorptiometry as abdominal fat% (AF%) or as the waist-to-hip ratio (WTH)) on serum lipids, lipoproteins, and apolipoproteins was investigated in 148 early postmenopausal women. All the women were healthy and none were taking medication known to influence the parameters studied. Smokers had significantly higher levels of triglycerides, low density lipoprotein cholesterol (LDL-C), and apolipoprotein B (P < 0.05), and higher ratios of LDL-C/HDL-C and apolipoprotein B/A-I (P < O.Ol), but lower levels of high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (P < 0.01). Moderate alcohol consumption was positively associated with HDL-C and apolipoprotein A-I (P -c0.001). Body weight and body mass index (BMI) tended to be positively associated with an atherogenic lipoprotein and apolipoprotein profile. However, body fat distribution parameters (AF% and WTH) were stronger predictors of lipoproteins and apolipoproteins than were body weight and BMI, which did not seem to be independent predictors of lipoproteins and apolipoproteins. We conclude that cigarette smoking and a central fat distribution have a significant, independent, negative influence on lipids, lipoproteins, and apolipoproteins, whereas moderate alcohol consumption has a positive effect on these parameters in early postmenopausal women. Key words: Lipids; Lipoproteins; Apolipoproteins; tion; Early postmenopausal women
Introduction
Cigarette smoking and obesity are associated with increased risk of cardiovascular disease and
Correspondence to: Jens Haarbo, Department of Clinical Chemistry, Glostrup Hospital, DK-2600 Glostrup, Denmark. 0021-9150/90/$03.50
Smoking; Alcohol consumption;
Body fat distribu-
are known to have a negative impact on lipid and lipoprotein metabolism [l]. It has recently been shown that not only obesity, but also the distribution of body fat, as measured indirectly by the waist to hip circumference ratio, is an independent cardiovascular risk factor in women [2]. We have recently shown that abdominal fat can be measured directly by dual photon absorptiometry, and
0 1990 Elsevier Scientific Publishers Ireland, Ltd.
240
with this method we showed a significant, positive correlation between central fat distribution and an atherogenic lipid and lipoprotein profile in elderly women [3]. But the impact of directly measured central fat on serum lipoproteins and apolipoproteins has never previously been examined in early postmenopausal women, which is a interesting group as prevention of future cardiovascular disease may be possible. In a recent large epidemiological investigation, moderate alcohol consumption was found to protect against cardiovascular disease [4]. This effect might partly be mediated through increased high density lipoprotein cholesterol in moderate drinkers. The association has been known for a long time in both men and women [5], whereas the effect of alcohol on apolipoproteins in early postmenopausal women has not been studied. We have therefore investigated the influence of smoking, directly measured abdominal fat, and alcohol consumption on serum lipids, lipoproteins, and apolipoproteins in early postmenopausal women.
Materials and methods
The study population consisted of 148 women, who were selected by means of a questionnaire, a medical examination, and a laboratory screening procedure to be a representative sample of healthy Danish postmenopausal women. They were 45-55 years old, had passed a natural menopause 6 months to 3 years previously, had no diseases and were not taking medication known to influence body composition or lipid metabolism, such as hormone replacement therapy, betablocking agents or diuretics. Informed consent was obtained from each participant according to the Helsinki Declaration II, and the trial was approved by the Ethical Committee of Copenhagen County. Body weight (kg) was measured to the nearest 0.1 kg wearing light indoor clothing, without shoes. Height (cm) was measured to the nearest 0.5 cm with the subject standing erect, without shoes. Body mass index (BMI) was calculated as body weight (kg) divided by the squared body height (m*). A single observer measured the waist-to-hip circumference ratio (WTH) at the levels of the
umbilicus and the greater trochanters, both to the nearest 0.5 cm, with the subject standing erect. Abdominal fat percentage (AF%) was measured in an area 15 cm wide between horizontal lines at the cranial edge of the second lumbar vertebra and the caudal edge of the 4th lumbar vertebra by dual photon absorptiometry [6]. During the 50-r& scanning procedure the subject lies supine with flexed hips and knees, with the lS3Gd source moving below and the NaI detector above in a rectilinear pattern. Data are collected in 1 X 4 mm pixels, yielding 3000-4000 soft tissue pixels in the area of interest. The long term precision is CV% = 9% [6]. Details of current smoking status and alcohol consumption were obtained by questionnaire [7]. Serum lipids, lipoproteins, and apolipoproteins
Blood samples were taken in the morning after an overnight fast and abstinence from tobacco. High density lipoprotein cholesterol (HDL-C) was separated from chylomicrons, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol by a phosphotungstateMgCl, precipitation technique [8]. Serum triglycerides (TG), total cholesterol (TC), and HDLC were determined enzymatically by a Chem I, Technicon, U.S.A. LDL-C was then estimated as described by Friedewald et al. [9]. The intra- and inter-assay variations were 1.7 and 3.7% (TC) and 3.0 and 8.2% (HDL-C), respectively. Lipoproteins were also determined using a Beckman L8-70 M ultracentrifuge and a Beckman 50.4 Ti rotor in a random subgroup (n = 15) of the 148 women in order to validate the lipoprotein measurements. The coefficients of correlation were for LDL-C 0.96 and for HDL-C 0.82; in neither were the slopes or the intercepts significantly different from 1 or 0, respectively. Apolipoprotein A-I, and B were measured by immunoturbidimetry as described by Biepponen [lo]. The intraassay variations for the apolipoproteins were approx. 3.5%. The correlation between HDL-C and apolipoprotein A-I and that between LDL-C and apolipoprotein B were statistically significant, r = 0.66 and r = 0.79, respectively (n = 148, P < 0.0001). Serum lipids, lipoproteins, and apolipoproteins were determined 10 times over a 1Zweek period in a subgroup (n = 45) in order to estimate the intraindividual coefficients of variation. These were
241 for TC (6.2%), LDL-C (9.4%), HDL-C apolipoprotein A-I (6.5%), and B (7.6%).
with an obesity parameter or alcohol consumption as covariates. These analyses were performed using the General Linear Models Procedure (GLM) of the Statistical Analysing System (SAS).
(8.2%)
Statistics Student’s t-test for unpaired data were used to compare smokers with non-smokers. The influence of smoking, body fat parameters (body weight, BMI, WTH, AF%), and alcohol consumption on serum lipids were investigated by analysis of covariance, relating each serum lipid to smoking
TABLE
Results
Smokers had lower HDL-C (P < 0.05) and apolipoprotein A-I (P < 0.01) and a higher apolipoprotein B/A, ratio (P -c 0.05) than did non-
1
STUDY POPULATION CHARACTERISTICS IN SMOKERS AND NON-SMOKERS AND DIFFERENCE BETWEEN SMOKERS AND NON-SMOKERS AFTER CORRECTION FOR POSSIBLE CONFOUNDING DIFFERENCE IN AF%
n
4% (yrs) Menopausal age (months) Body weight (kg) Body mass index (kg/m’) WTH Abdominal fat% TC (mmol/l) TG (mmol/l) LDL-C (mmol/l) HDL-C (mmol/l) LDL-C/HDL-C Apolipoprotein B (g/l) Apolipoprotein A-I (g/l) Apolipoprotein B/A-I Comparisons
TABLE
between
non-smokers
Non-smokers (mean f SD)
Smokers (mean f SD)
76 51.2 f 2.2 20.6 f 9.2 66.8 *to.5 24.9 * 3.1 0.75+ 0.05 32.5 f12.0 6.42* 1.19 0.99* 0.49 4.26f 1.19 1.67+ 0.45 2.78+ 1.23 0.98+ 0.25 1.53+ 0.26 0.66* 0.19
72 50.8 + 2.1 23.2 + 9.2 63.1 f 9.85 23.9 + 3.1 0.76+ 0.05 27.4 +11.4 * 6.52+ 1.18 1.07* 0.37 4.52+ 1.15 1.51+ 0.31 * 3.16f 1.16 1.03+ 0.23 1.43+ 0.17 ** 0.73* 0.16 *
and smokers:
0.26*0.19 0.14+0.07 0.45 +0.19 _ .0.21* 0.06 0.61+0.18 0.09 &-0.04 0.10 f 0.04 0.10 *to.03
P -c0.01, *** P < 0.001. Abbreviations:
* * ** ** * ** *** see text.
2
RELATION OF OBESITY PARAMETERS FOR SMOKING STATUS IN ANALYSIS General
TO SERUM LIPIDS, LIPOPROTEINS, AND OF COVARIANCE (PARTIAL COEFFICIENTS obesity parameters
Body weight TC TG LDL-C HDL-C Apolipoprotein Apolipoprotein LDL-C/HDL-C Apolipoprotein *
* P < 0.05, * *
Difference between smokers and non-smokers after correction for AF% (mean f SE)
B A-I B/A-I
0.11 0.22 0.15 -0.23 0.19 -0.14 0.25 0.25
** ** * ** **
P c 0.05, ** P < 0.01, ** * P < 0.0001.
APOLIPOPROTEINS OF CORRELATION)
Fat distribution BMI
WTH
0.16 0.27 * * 0.20 -0.21 0.25 -0.12 0.30 0.30
* ** ** ** **
0.10 0.34 0.19 -0.41 0.36 -0.19 0.41 0.42
parameters AFS
*** * *** *** * *** ***
0.30 0.33 0.35 -0.33 0.38 - 0.08 0.44 0.39
** *** *** *** *** *** ***
ADJUSTED
*paluaAald aq UBDawasyp _wIn~sea -orpm~ anun 3r dnoti %uylsa.ralu! ut? ‘IaAaMog ‘y sg~, .uatuoM @snedouatulsod %unoA ueyl laylo 01 uoynw yly palaIodwxa aq pInoqs S%UIJXI~~ ayl prrr? ‘s~o~x~ 8urpuno3uo~ 30 %ufz~~g s;r u%fsap Apnls luasald ayl30 &!t?lw~pe ayJ .uatuoM yspa Iesnedouaurlsod LI.rea 30 uoyeIndod a,ylt?luas -a.IdaJ e yip lno pay3 SAM 6pnls 1uasaJd ayJ
*slaJorus-uou uy 10 sla?ows u! layl!a ‘szalaurvnzd it?J lcpoq ayl 30 Aua 01 pal-eIaJ LpuecguZ&s lou WM uoyldurnsuo:, Ioyo~Iv ‘I-V uraloJdodgodv JO yIaH uo snlvls %ugours pvt! uogdwnsuo:, Ioyo:, -Ia 30 y9a33a Bug9waluy lw~gy?@ ou SEM alaqL *snlols %u~yows luarm:, 103 Ougsnfpt! lal3e (Iooo*o 1 a) I-V uralosdod?Iode PW (wo > d) maH pur! uoydtunsuo:, [oqocy~ uaawlaq uoyt?IalJoD ‘aylysod ‘1~~3~~s ayl salallsnII! z -%y fsasw IF uy 60.0 > 1 pgnzd) uralordodgodr! JO u!aloJd -odg ‘p!dn 1cw 01 palvIa Qluapuadapur Q.IKN~~ -8rs sasdpzut! asayl uf SBM 1~8 JOU ly%rah Icpoq JaaylraN *(sass:, IIe u! go.0 > d > Ioofyo) soge~ ‘tx ~-v/a u!aloIdod!Iode put! ‘3--IaHh--IaT ayl 01 palepl dIaA!l!sod pur! ‘I-V tyalo.rdodgode pue 3-TaI-I 01 paltzIa1 ICIanyt?%au SBM H,CM se=aqM
‘3-7aH/3-7aq
oy=
q
pue
‘3-7aT
‘DJ_ 01 paleIaJ hIaAg!sOd STEM gY;dV‘sasAIeue asag uI *snlels %ugours lualm:, .x03Ouylsn[pt? lagv sJaj -awend 1~36poq I@ 01 palvIa alaM spldg unuas aJaIayMa~r.nzyAo3 30 s!sAIaut! w ut par.uJguoD SBM S~J_ *(Iwa pun ly%!am 1cpoq) sJalaunzred Qsaqo IelauaZ! a.raM uayl suraloJdodnodc pue suyold -odg 30 slowpald ra%uorls dIIwaua% alaw (HLM pus ygt;av) swau.wlt?d uoynqyyp 19 lcpoa *I %a u! umoys s! sptdg uo ~+JV 30 awanuur lu~~3~%~s au ‘I-V ufaloldodgoda put! D-?aH ql;[~ pale -!~~ss~ AIaayBau pua ‘IV/g uyaloldodgode put!
-eL) slayours-uou ut?ql oysl yIaH/yIaT put! ‘8 ujaloldodqodt? ‘yIa1 ‘9,~ lay%lq AIlua~3~ -%is peq Q2uogtppe wyours &IV ui saDuaJa33tp 30 va33a %u~puno3uo~ aIq!ssod ayl 103 uoy~~.~o~ It?~~lsyels Ialp ‘aJouuaylJn,I *(I aIqvL) slayours
II
I
0
9'0 0.0 L'O 8.0
WV
‘xaH/ma? ‘8uraloJdodnod~ 'map ‘tx
‘a~, qp palt?!wsse LIagrsod aJaM sJalauren?d lt?J lcpoq ‘Ip2JaAo ‘snlws Bu~>lours waun9 103 %ugsn[pe ~13~ suralordodgode put? ‘s?aloJdodg ‘sP!d?I uo (WV Pup ‘HLM ‘IfUI ‘ly%!aM APoq) sralatuwd 1~36poq 30 lcta33aaql SMOGS2 aIqv,I, ‘(I aIq”L) HLM 10 ‘IJWI ‘ly%!aM Apoq u! uaas st3~ a3uaJaJyp luwg~~s A~~ecy -syals ou saalaqM ‘@JO > d) slaqours-uou u! ut?yl uy .raMoIdIluwgyu%~s SAMgdV au ‘(I aIq slayows
243 Our study demonstrates that smokers have significantly more atherogenic lipoproteins and apolipoproteins than do non-smokers, differences which may partly explain the increased risk of cardiovascular disease in smokers [ll]. Previous studies have shown that smokers have higher LDL-C and lower HDL-C and apolipoprotein A-I than non-smokers [1,12-161. With regard to apolipoprotein B, previous data are lacking on the influence of cigarette smoking in early postmenopausal women. The impact of smoking on apolipoprotein B was, moreover, not considered in a recent analysis of pooled data from 54 studies on the association between cigarette smoking and serum lipids, lipoproteins, and apolipoproteins
WI. In our study body weight and BMI tended to be associated with an atherogenic lipid and lipoprotein profile. These findings are consistent with those of other studies [17]. Obesity has earlier been demonstrated to be an independent predictor of cardiovascular disease, but lipoproteins were not considered in these analyses [18]. Inclusion of these parameters might have modified the conclusion, as the effect of obesity on lipoproteins corresponds to the range of HDL-C differences reported to be associated with mortality from coronary heart disease [19]. However, not only obesity but also the distribution of body fat is a risk factor for cardiovascular disease in women [2]. We [3] and others [20-231 have recently shown, by means of different methods, that central fat is associated with a more atherogenic lipid and lipoprotein profile in elderly and premenopausal women. The present study demonstrates a significant and independent association between directly, as well as indirectly, measured abdominal fatness and an atherogenic lipid and apolipoprotein profile in early postmenopausal women. Moreover, our study suggests that abdominal fatness is more closely related to an atherogenic lipid profile than are body weight and BMI. The mechanism behind the significant impact of fat distribution is largely unknown, but some data suggest that increased androgenic activity may in part be responsible for localization of fat in the upper body and the atherogenic lipid profile [24]. It has also been suggested that insulin may act as a mediating
metabolic factor in the interrelationship between body fat distribution and blood lipids [22]. Moderate alcohol consumption was in our study significantly positively related to HDL-C and apolipoprotein A-I. In the case of HDL-C our findings agree with a previous study in women [5], whereas data on the association between alcohol consumption and apolipoprotein A-I in women are conflicting [12,13]. A large prospective study has suggested that moderate alcohol consumption reduces the risk of coronary heart disease in middle-aged women [4]. Neither HDL-C nor apolipoprotein A-I were determined in that study, but changes in these parameters may partly explain the beneficial effect of a moderate alcohol consumption. We conclude that cigarette smoking, and a central fat distribution have a significant, independent, negative impact on lipids, lipoproteins, as well as on apolipoproteins, whereas moderate alcohol consumption has a positive effect on these parameters in early postmenopausal women. References 1 Bush, T.L., Fried, L.P. and Barrett-Connor, E., Cholesterol, lipoproteins, and coronary heart disease in women, Clin. Chem., 34 (1988) B60. 2 Lapidus, L., Bengtsson, C., Larsson, B., Pennert, K., Rybo, E. and Sjostrom, L., Distribution of adipose tissue and risk of cardiovascular disease and death: a 12 year follow up of participants in the population study of women in Gothenburg, Sweden, Br. Med. J., 289 (1984) 1257. 3 Haarbo, J., Hassager, C., Riis, B.J. and Christiansen. C., Relation of body fat distribution to serum lipids and lipoproteins in elderly women, Atherosclerosis, 80 (1989) 57. 4 Stampfer. M.J., Colditz, G.A., Willett, WC., Speizer, F.E. and Hennekens, C.H., A prospective study of moderate alcohol consumption and the risk of coronary disease and stroke in women, N. Engl. J. Med., 319 (1988) 267. 5 Ernst, N., Fischer, M., Smith, W., Gordon, T., Rifkind, B.M., Little, J.A., Mishkel, M.A. and Williams, O.D., The association of plasma high-density lipoprotein cholesterol with dietary intake and alcohol consumption, Circulation, 62 (1980) 41. 6 Schlemmer, A., Hassager, C., Haarbo, J. and Christiansen, C., Direct measurement of abdominal fat by dual photon absorptiometry, Int. J. Obes., 14 (1990) 603. 7 Jensen. J., Christiansen, C. and Rodbro, P.. Cigarette smoking, serum estrogens, and bone loss during bormone-replacement therapy early after menopause. N. Engl. J. Med. 313 (1985) 973.
244 8 Draeger, B., Wahlefeld, A.W. and Ziegenhom, J., Eine praktikable Methode zur HDL-cholesterin-bestimmung, Lab. Med., 6 (1982) 198. 9 Friedewald, W.T., Levy, RI. and Frederickson, D.S., Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge, Clin. Chem., 18 (1972) 499. 10 Riepponen, P., Mamiemi, J. and Rautaoja, T., Immunoturbidimetric determination of apolipoproteins A-l and B in serum, Stand. J. Clin. Lab. Invest., 47 (1987) 739. 11 Friedman, G.D., Dales, L.G. and Ury, H.K., Mortality in middle-aged smokers and nonsmokers, N. Engl. J. Med., 300 (1979) 213. 12 Gomo, Z.A.R., The effect of age, sex, alcohol consumption and cigarette smoking on serum concentrations of lipids and apolipoproteins in Zimbabwean blacks, Atherosclerosis, 61 (1986) 149. 13 Haffner, S.M., Applebaum-Bowden, D., Wahl, P.W., Hoover, J.J., Wamick, G.R., Albers, J.J. and Hazard, W.R., Epidemiological correlates of high density lipoprotein subfractions, apolipoproteins A-I, A-II, and D, and lecithin cholesterol acyltransferase, Arteriosclerosis, 5 (1985) 169. 14 Taylor, K.G., Carter, T.J., Valente, A.J., Wright, A.D., Smith, J.H. and Matthews, K.A., Sex differences in the relationships between obesity, alcohol consumption and cigarette smoking and serum lipid and apolipoprotein concentrations in a normal population, Atherosclerosis, 31 (1981) 11. 15 Dedonder-Decoopman, E., Fievet-Desreumaux, C., Campos, E., Moulin, S., Dewailly, P., Sezille, G. and Jaillard, J., Plasma levels of VLDL- + LDL-cholesterol, HDLcholesterol, triglycerides and apoproteins B and A-I in a healthy population, Atherosclerosis, 37 (1980) 559. 16 Craig, W.Y., Palomaki, G.E., and Haddow, J.E., Cigarette smoking and serum lipid and lipoprotein concentrations: an analysis of published data, Br. Med. J., 298 (1989) 784.
17 Comror, S.L., Connor, W.E., Sexton, G., Calvin, L. and Bacon, S., The effects of age, body weight and family relationships on plasma lipoproteins and lipids in men, women and children of randomly selected families, Circulation, 65 (1982) 1290. 18 Hubert, H.B., Feinleib, M., McNamara, P.M., and Castelli, W.P., Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham heart study, Circulation, 67 (1983) 968. 19 Glueck, C.J., Taylor, H.L., Jacobs, D., Morrison, J.A., Beaglehole, R. and Williams, O.D., Plasma high-density lipoprotein cholesterol: association with measurements of body mass, Circulation, 62 (1980) 62. 20 Baumgartner, R.N., Roche, A.F., Chumela, W.C., Siervogel, R.M. and Glueck, C.J., Fatness and fat patterns: association with plasma lipids and blood pressure in adults, 18 to 57 years of age, Am. J. Epidemiol., 126 (1987) 614. 21 Anderson, A.J., Sobocinski, K.A., Freedman, D.S., Barboriak, J.J., Rimm, A.A. and Gruchow, H.W., Body fat distribution, plasma lipids and lipoproteins, Arteriosclerosis, 8 (1988) 88. 22 Marti, B., Suter, E., Riesen, W.F., Tschopp, A. and Wanner, H-U., Antropometric and lifestyle correlates of serum lipoprotein and apolipoprotein among normal non-smoking men and women, Atherosclerosis, 75 (1989) 111. 23 Osthmd, R.E., Staten, M., Kohrt, W.M., Schultz, J. and Malley, M., The ratio of waist to hip circumference, plasma insulin level, and glucose intolerance as independent predictors of the HDL2 cholesterol level in older adults, N. Engl. J. Med., 322 (1990) 229. 24 Evans, D.J., Hoffmann, R.G., Kalkhoff, R.K. and Kissebah, A.H., Relationship of androgenic activity to body fat topography, fat cell morphology, and metabolic aberrations in premenopausal women, J. Clin. Endocrinol. Metab., 57 (1983) 304.
Atherosclerosis, 84 (1990) 239-244 Elsevier Scientific Publishers Ireland, Ltd.
ATHERO 04545
Influence of smoking, body fat distribution, and alcohol consumption on serum lipids, lipoproteins, and apolipoproteins in early postmenopausal women Jens Haarbo, Christian Hassager, Annette Schlemmer and Claus Christiansen Department of Clinical Chemistry, Glostrup Hospital, University of Copenhagen, DK-2600 Glostrup (Denmark) (Received 4 April, 1990) (Revised, received 22 June, 1990) (Accepted 29 June, 1990)
The impact of smoking, alcohol consumption, obesity, and body fat distribution (measured either directly by dual photon absorptiometry as abdominal fat% (AF%) or as the waist-to-hip ratio (WTH)) on serum lipids, lipoproteins, and apolipoproteins was investigated in 148 early postmenopausal women. All the women were healthy and none were taking medication known to influence the parameters studied. Smokers had significantly higher levels of triglycerides, low density lipoprotein cholesterol (LDL-C), and apolipoprotein B (P < 0.05), and higher ratios of LDL-C/HDL-C and apolipoprotein B/A-I (P < O.Ol), but lower levels of high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (P < 0.01). Moderate alcohol consumption was positively associated with HDL-C and apolipoprotein A-I (P -c0.001). Body weight and body mass index (BMI) tended to be positively associated with an atherogenic lipoprotein and apolipoprotein profile. However, body fat distribution parameters (AF% and WTH) were stronger predictors of lipoproteins and apolipoproteins than were body weight and BMI, which did not seem to be independent predictors of lipoproteins and apolipoproteins. We conclude that cigarette smoking and a central fat distribution have a significant, independent, negative influence on lipids, lipoproteins, and apolipoproteins, whereas moderate alcohol consumption has a positive effect on these parameters in early postmenopausal women. Key words: Lipids; Lipoproteins; Apolipoproteins; tion; Early postmenopausal women
Introduction
Cigarette smoking and obesity are associated with increased risk of cardiovascular disease and
Correspondence to: Jens Haarbo, Department of Clinical Chemistry, Glostrup Hospital, DK-2600 Glostrup, Denmark. 0021-9150/90/$03.50
Smoking; Alcohol consumption;
Body fat distribu-
are known to have a negative impact on lipid and lipoprotein metabolism [l]. It has recently been shown that not only obesity, but also the distribution of body fat, as measured indirectly by the waist to hip circumference ratio, is an independent cardiovascular risk factor in women [2]. We have recently shown that abdominal fat can be measured directly by dual photon absorptiometry, and
0 1990 Elsevier Scientific Publishers Ireland, Ltd.
240
with this method we showed a significant, positive correlation between central fat distribution and an atherogenic lipid and lipoprotein profile in elderly women [3]. But the impact of directly measured central fat on serum lipoproteins and apolipoproteins has never previously been examined in early postmenopausal women, which is a interesting group as prevention of future cardiovascular disease may be possible. In a recent large epidemiological investigation, moderate alcohol consumption was found to protect against cardiovascular disease [4]. This effect might partly be mediated through increased high density lipoprotein cholesterol in moderate drinkers. The association has been known for a long time in both men and women [5], whereas the effect of alcohol on apolipoproteins in early postmenopausal women has not been studied. We have therefore investigated the influence of smoking, directly measured abdominal fat, and alcohol consumption on serum lipids, lipoproteins, and apolipoproteins in early postmenopausal women.
Materials and methods
The study population consisted of 148 women, who were selected by means of a questionnaire, a medical examination, and a laboratory screening procedure to be a representative sample of healthy Danish postmenopausal women. They were 45-55 years old, had passed a natural menopause 6 months to 3 years previously, had no diseases and were not taking medication known to influence body composition or lipid metabolism, such as hormone replacement therapy, betablocking agents or diuretics. Informed consent was obtained from each participant according to the Helsinki Declaration II, and the trial was approved by the Ethical Committee of Copenhagen County. Body weight (kg) was measured to the nearest 0.1 kg wearing light indoor clothing, without shoes. Height (cm) was measured to the nearest 0.5 cm with the subject standing erect, without shoes. Body mass index (BMI) was calculated as body weight (kg) divided by the squared body height (m*). A single observer measured the waist-to-hip circumference ratio (WTH) at the levels of the
umbilicus and the greater trochanters, both to the nearest 0.5 cm, with the subject standing erect. Abdominal fat percentage (AF%) was measured in an area 15 cm wide between horizontal lines at the cranial edge of the second lumbar vertebra and the caudal edge of the 4th lumbar vertebra by dual photon absorptiometry [6]. During the 50-r& scanning procedure the subject lies supine with flexed hips and knees, with the lS3Gd source moving below and the NaI detector above in a rectilinear pattern. Data are collected in 1 X 4 mm pixels, yielding 3000-4000 soft tissue pixels in the area of interest. The long term precision is CV% = 9% [6]. Details of current smoking status and alcohol consumption were obtained by questionnaire [7]. Serum lipids, lipoproteins, and apolipoproteins
Blood samples were taken in the morning after an overnight fast and abstinence from tobacco. High density lipoprotein cholesterol (HDL-C) was separated from chylomicrons, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol by a phosphotungstateMgCl, precipitation technique [8]. Serum triglycerides (TG), total cholesterol (TC), and HDLC were determined enzymatically by a Chem I, Technicon, U.S.A. LDL-C was then estimated as described by Friedewald et al. [9]. The intra- and inter-assay variations were 1.7 and 3.7% (TC) and 3.0 and 8.2% (HDL-C), respectively. Lipoproteins were also determined using a Beckman L8-70 M ultracentrifuge and a Beckman 50.4 Ti rotor in a random subgroup (n = 15) of the 148 women in order to validate the lipoprotein measurements. The coefficients of correlation were for LDL-C 0.96 and for HDL-C 0.82; in neither were the slopes or the intercepts significantly different from 1 or 0, respectively. Apolipoprotein A-I, and B were measured by immunoturbidimetry as described by Biepponen [lo]. The intraassay variations for the apolipoproteins were approx. 3.5%. The correlation between HDL-C and apolipoprotein A-I and that between LDL-C and apolipoprotein B were statistically significant, r = 0.66 and r = 0.79, respectively (n = 148, P < 0.0001). Serum lipids, lipoproteins, and apolipoproteins were determined 10 times over a 1Zweek period in a subgroup (n = 45) in order to estimate the intraindividual coefficients of variation. These were
241 for TC (6.2%), LDL-C (9.4%), HDL-C apolipoprotein A-I (6.5%), and B (7.6%).
with an obesity parameter or alcohol consumption as covariates. These analyses were performed using the General Linear Models Procedure (GLM) of the Statistical Analysing System (SAS).
(8.2%)
Statistics Student’s t-test for unpaired data were used to compare smokers with non-smokers. The influence of smoking, body fat parameters (body weight, BMI, WTH, AF%), and alcohol consumption on serum lipids were investigated by analysis of covariance, relating each serum lipid to smoking
TABLE
Results
Smokers had lower HDL-C (P < 0.05) and apolipoprotein A-I (P < 0.01) and a higher apolipoprotein B/A, ratio (P -c 0.05) than did non-
1
STUDY POPULATION CHARACTERISTICS IN SMOKERS AND NON-SMOKERS AND DIFFERENCE BETWEEN SMOKERS AND NON-SMOKERS AFTER CORRECTION FOR POSSIBLE CONFOUNDING DIFFERENCE IN AF%
n
4% (yrs) Menopausal age (months) Body weight (kg) Body mass index (kg/m’) WTH Abdominal fat% TC (mmol/l) TG (mmol/l) LDL-C (mmol/l) HDL-C (mmol/l) LDL-C/HDL-C Apolipoprotein B (g/l) Apolipoprotein A-I (g/l) Apolipoprotein B/A-I Comparisons
TABLE
between
non-smokers
Non-smokers (mean f SD)
Smokers (mean f SD)
76 51.2 f 2.2 20.6 f 9.2 66.8 *to.5 24.9 * 3.1 0.75+ 0.05 32.5 f12.0 6.42* 1.19 0.99* 0.49 4.26f 1.19 1.67+ 0.45 2.78+ 1.23 0.98+ 0.25 1.53+ 0.26 0.66* 0.19
72 50.8 + 2.1 23.2 + 9.2 63.1 f 9.85 23.9 + 3.1 0.76+ 0.05 27.4 +11.4 * 6.52+ 1.18 1.07* 0.37 4.52+ 1.15 1.51+ 0.31 * 3.16f 1.16 1.03+ 0.23 1.43+ 0.17 ** 0.73* 0.16 *
and smokers:
0.26*0.19 0.14+0.07 0.45 +0.19 _ .0.21* 0.06 0.61+0.18 0.09 &-0.04 0.10 f 0.04 0.10 *to.03
P -c0.01, *** P < 0.001. Abbreviations:
* * ** ** * ** *** see text.
2
RELATION OF OBESITY PARAMETERS FOR SMOKING STATUS IN ANALYSIS General
TO SERUM LIPIDS, LIPOPROTEINS, AND OF COVARIANCE (PARTIAL COEFFICIENTS obesity parameters
Body weight TC TG LDL-C HDL-C Apolipoprotein Apolipoprotein LDL-C/HDL-C Apolipoprotein *
* P < 0.05, * *
Difference between smokers and non-smokers after correction for AF% (mean f SE)
B A-I B/A-I
0.11 0.22 0.15 -0.23 0.19 -0.14 0.25 0.25
** ** * ** **
P c 0.05, ** P < 0.01, ** * P < 0.0001.
APOLIPOPROTEINS OF CORRELATION)
Fat distribution BMI
WTH
0.16 0.27 * * 0.20 -0.21 0.25 -0.12 0.30 0.30
* ** ** ** **
0.10 0.34 0.19 -0.41 0.36 -0.19 0.41 0.42
parameters AFS
*** * *** *** * *** ***
0.30 0.33 0.35 -0.33 0.38 - 0.08 0.44 0.39
** *** *** *** *** *** ***
ADJUSTED
*paluaAald aq UBDawasyp _wIn~sea -orpm~ anun 3r dnoti %uylsa.ralu! ut? ‘IaAaMog ‘y sg~, .uatuoM @snedouatulsod %unoA ueyl laylo 01 uoynw yly palaIodwxa aq pInoqs S%UIJXI~~ ayl prrr? ‘s~o~x~ 8urpuno3uo~ 30 %ufz~~g s;r u%fsap Apnls luasald ayl30 &!t?lw~pe ayJ .uatuoM yspa Iesnedouaurlsod LI.rea 30 uoyeIndod a,ylt?luas -a.IdaJ e yip lno pay3 SAM 6pnls 1uasaJd ayJ
*slaJorus-uou uy 10 sla?ows u! layl!a ‘szalaurvnzd it?J lcpoq ayl 30 Aua 01 pal-eIaJ LpuecguZ&s lou WM uoyldurnsuo:, Ioyo~Iv ‘I-V uraloJdodgodv JO yIaH uo snlvls %ugours pvt! uogdwnsuo:, Ioyo:, -Ia 30 y9a33a Bug9waluy lw~gy?@ ou SEM alaqL *snlols %u~yows luarm:, 103 Ougsnfpt! lal3e (Iooo*o 1 a) I-V uralosdod?Iode PW (wo > d) maH pur! uoydtunsuo:, [oqocy~ uaawlaq uoyt?IalJoD ‘aylysod ‘1~~3~~s ayl salallsnII! z -%y fsasw IF uy 60.0 > 1 pgnzd) uralordodgodr! JO u!aloJd -odg ‘p!dn 1cw 01 palvIa Qluapuadapur Q.IKN~~ -8rs sasdpzut! asayl uf SBM 1~8 JOU ly%rah Icpoq JaaylraN *(sass:, IIe u! go.0 > d > Ioofyo) soge~ ‘tx ~-v/a u!aloIdod!Iode put! ‘3--IaHh--IaT ayl 01 palepl dIaA!l!sod pur! ‘I-V tyalo.rdodgode pue 3-TaI-I 01 paltzIa1 ICIanyt?%au SBM H,CM se=aqM
‘3-7aH/3-7aq
oy=
q
pue
‘3-7aT
‘DJ_ 01 paleIaJ hIaAg!sOd STEM gY;dV‘sasAIeue asag uI *snlels %ugours lualm:, .x03Ouylsn[pt? lagv sJaj -awend 1~36poq I@ 01 palvIa alaM spldg unuas aJaIayMa~r.nzyAo3 30 s!sAIaut! w ut par.uJguoD SBM S~J_ *(Iwa pun ly%!am 1cpoq) sJalaunzred Qsaqo IelauaZ! a.raM uayl suraloJdodnodc pue suyold -odg 30 slowpald ra%uorls dIIwaua% alaw (HLM pus ygt;av) swau.wlt?d uoynqyyp 19 lcpoa *I %a u! umoys s! sptdg uo ~+JV 30 awanuur lu~~3~%~s au ‘I-V ufaloldodgoda put! D-?aH ql;[~ pale -!~~ss~ AIaayBau pua ‘IV/g uyaloldodgode put!
-eL) slayours-uou ut?ql oysl yIaH/yIaT put! ‘8 ujaloldodqodt? ‘yIa1 ‘9,~ lay%lq AIlua~3~ -%is peq Q2uogtppe wyours &IV ui saDuaJa33tp 30 va33a %u~puno3uo~ aIq!ssod ayl 103 uoy~~.~o~ It?~~lsyels Ialp ‘aJouuaylJn,I *(I aIqvL) slayours
II
I
0
9'0 0.0 L'O 8.0
WV
‘xaH/ma? ‘8uraloJdodnod~ 'map ‘tx
‘a~, qp palt?!wsse LIagrsod aJaM sJalauren?d lt?J lcpoq ‘Ip2JaAo ‘snlws Bu~>lours waun9 103 %ugsn[pe ~13~ suralordodgode put? ‘s?aloJdodg ‘sP!d?I uo (WV Pup ‘HLM ‘IfUI ‘ly%!aM APoq) sralatuwd 1~36poq 30 lcta33aaql SMOGS2 aIqv,I, ‘(I aIq”L) HLM 10 ‘IJWI ‘ly%!aM Apoq u! uaas st3~ a3uaJaJyp luwg~~s A~~ecy -syals ou saalaqM ‘@JO > d) slaqours-uou u! ut?yl uy .raMoIdIluwgyu%~s SAMgdV au ‘(I aIq slayows
243 Our study demonstrates that smokers have significantly more atherogenic lipoproteins and apolipoproteins than do non-smokers, differences which may partly explain the increased risk of cardiovascular disease in smokers [ll]. Previous studies have shown that smokers have higher LDL-C and lower HDL-C and apolipoprotein A-I than non-smokers [1,12-161. With regard to apolipoprotein B, previous data are lacking on the influence of cigarette smoking in early postmenopausal women. The impact of smoking on apolipoprotein B was, moreover, not considered in a recent analysis of pooled data from 54 studies on the association between cigarette smoking and serum lipids, lipoproteins, and apolipoproteins
WI. In our study body weight and BMI tended to be associated with an atherogenic lipid and lipoprotein profile. These findings are consistent with those of other studies [17]. Obesity has earlier been demonstrated to be an independent predictor of cardiovascular disease, but lipoproteins were not considered in these analyses [18]. Inclusion of these parameters might have modified the conclusion, as the effect of obesity on lipoproteins corresponds to the range of HDL-C differences reported to be associated with mortality from coronary heart disease [19]. However, not only obesity but also the distribution of body fat is a risk factor for cardiovascular disease in women [2]. We [3] and others [20-231 have recently shown, by means of different methods, that central fat is associated with a more atherogenic lipid and lipoprotein profile in elderly and premenopausal women. The present study demonstrates a significant and independent association between directly, as well as indirectly, measured abdominal fatness and an atherogenic lipid and apolipoprotein profile in early postmenopausal women. Moreover, our study suggests that abdominal fatness is more closely related to an atherogenic lipid profile than are body weight and BMI. The mechanism behind the significant impact of fat distribution is largely unknown, but some data suggest that increased androgenic activity may in part be responsible for localization of fat in the upper body and the atherogenic lipid profile [24]. It has also been suggested that insulin may act as a mediating
metabolic factor in the interrelationship between body fat distribution and blood lipids [22]. Moderate alcohol consumption was in our study significantly positively related to HDL-C and apolipoprotein A-I. In the case of HDL-C our findings agree with a previous study in women [5], whereas data on the association between alcohol consumption and apolipoprotein A-I in women are conflicting [12,13]. A large prospective study has suggested that moderate alcohol consumption reduces the risk of coronary heart disease in middle-aged women [4]. Neither HDL-C nor apolipoprotein A-I were determined in that study, but changes in these parameters may partly explain the beneficial effect of a moderate alcohol consumption. We conclude that cigarette smoking, and a central fat distribution have a significant, independent, negative impact on lipids, lipoproteins, as well as on apolipoproteins, whereas moderate alcohol consumption has a positive effect on these parameters in early postmenopausal women. References 1 Bush, T.L., Fried, L.P. and Barrett-Connor, E., Cholesterol, lipoproteins, and coronary heart disease in women, Clin. Chem., 34 (1988) B60. 2 Lapidus, L., Bengtsson, C., Larsson, B., Pennert, K., Rybo, E. and Sjostrom, L., Distribution of adipose tissue and risk of cardiovascular disease and death: a 12 year follow up of participants in the population study of women in Gothenburg, Sweden, Br. Med. J., 289 (1984) 1257. 3 Haarbo, J., Hassager, C., Riis, B.J. and Christiansen. C., Relation of body fat distribution to serum lipids and lipoproteins in elderly women, Atherosclerosis, 80 (1989) 57. 4 Stampfer. M.J., Colditz, G.A., Willett, WC., Speizer, F.E. and Hennekens, C.H., A prospective study of moderate alcohol consumption and the risk of coronary disease and stroke in women, N. Engl. J. Med., 319 (1988) 267. 5 Ernst, N., Fischer, M., Smith, W., Gordon, T., Rifkind, B.M., Little, J.A., Mishkel, M.A. and Williams, O.D., The association of plasma high-density lipoprotein cholesterol with dietary intake and alcohol consumption, Circulation, 62 (1980) 41. 6 Schlemmer, A., Hassager, C., Haarbo, J. and Christiansen, C., Direct measurement of abdominal fat by dual photon absorptiometry, Int. J. Obes., 14 (1990) 603. 7 Jensen. J., Christiansen, C. and Rodbro, P.. Cigarette smoking, serum estrogens, and bone loss during bormone-replacement therapy early after menopause. N. Engl. J. Med. 313 (1985) 973.
244 8 Draeger, B., Wahlefeld, A.W. and Ziegenhom, J., Eine praktikable Methode zur HDL-cholesterin-bestimmung, Lab. Med., 6 (1982) 198. 9 Friedewald, W.T., Levy, RI. and Frederickson, D.S., Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge, Clin. Chem., 18 (1972) 499. 10 Riepponen, P., Mamiemi, J. and Rautaoja, T., Immunoturbidimetric determination of apolipoproteins A-l and B in serum, Stand. J. Clin. Lab. Invest., 47 (1987) 739. 11 Friedman, G.D., Dales, L.G. and Ury, H.K., Mortality in middle-aged smokers and nonsmokers, N. Engl. J. Med., 300 (1979) 213. 12 Gomo, Z.A.R., The effect of age, sex, alcohol consumption and cigarette smoking on serum concentrations of lipids and apolipoproteins in Zimbabwean blacks, Atherosclerosis, 61 (1986) 149. 13 Haffner, S.M., Applebaum-Bowden, D., Wahl, P.W., Hoover, J.J., Wamick, G.R., Albers, J.J. and Hazard, W.R., Epidemiological correlates of high density lipoprotein subfractions, apolipoproteins A-I, A-II, and D, and lecithin cholesterol acyltransferase, Arteriosclerosis, 5 (1985) 169. 14 Taylor, K.G., Carter, T.J., Valente, A.J., Wright, A.D., Smith, J.H. and Matthews, K.A., Sex differences in the relationships between obesity, alcohol consumption and cigarette smoking and serum lipid and apolipoprotein concentrations in a normal population, Atherosclerosis, 31 (1981) 11. 15 Dedonder-Decoopman, E., Fievet-Desreumaux, C., Campos, E., Moulin, S., Dewailly, P., Sezille, G. and Jaillard, J., Plasma levels of VLDL- + LDL-cholesterol, HDLcholesterol, triglycerides and apoproteins B and A-I in a healthy population, Atherosclerosis, 37 (1980) 559. 16 Craig, W.Y., Palomaki, G.E., and Haddow, J.E., Cigarette smoking and serum lipid and lipoprotein concentrations: an analysis of published data, Br. Med. J., 298 (1989) 784.
17 Comror, S.L., Connor, W.E., Sexton, G., Calvin, L. and Bacon, S., The effects of age, body weight and family relationships on plasma lipoproteins and lipids in men, women and children of randomly selected families, Circulation, 65 (1982) 1290. 18 Hubert, H.B., Feinleib, M., McNamara, P.M., and Castelli, W.P., Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham heart study, Circulation, 67 (1983) 968. 19 Glueck, C.J., Taylor, H.L., Jacobs, D., Morrison, J.A., Beaglehole, R. and Williams, O.D., Plasma high-density lipoprotein cholesterol: association with measurements of body mass, Circulation, 62 (1980) 62. 20 Baumgartner, R.N., Roche, A.F., Chumela, W.C., Siervogel, R.M. and Glueck, C.J., Fatness and fat patterns: association with plasma lipids and blood pressure in adults, 18 to 57 years of age, Am. J. Epidemiol., 126 (1987) 614. 21 Anderson, A.J., Sobocinski, K.A., Freedman, D.S., Barboriak, J.J., Rimm, A.A. and Gruchow, H.W., Body fat distribution, plasma lipids and lipoproteins, Arteriosclerosis, 8 (1988) 88. 22 Marti, B., Suter, E., Riesen, W.F., Tschopp, A. and Wanner, H-U., Antropometric and lifestyle correlates of serum lipoprotein and apolipoprotein among normal non-smoking men and women, Atherosclerosis, 75 (1989) 111. 23 Osthmd, R.E., Staten, M., Kohrt, W.M., Schultz, J. and Malley, M., The ratio of waist to hip circumference, plasma insulin level, and glucose intolerance as independent predictors of the HDL2 cholesterol level in older adults, N. Engl. J. Med., 322 (1990) 229. 24 Evans, D.J., Hoffmann, R.G., Kalkhoff, R.K. and Kissebah, A.H., Relationship of androgenic activity to body fat topography, fat cell morphology, and metabolic aberrations in premenopausal women, J. Clin. Endocrinol. Metab., 57 (1983) 304.
