Metabolic Syndrome and Health-related Quality of Life in Obese Individuals Seeking Weight Reduction

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1 Metbolic Syndrome nd Helth-relted Qulity of Life in Obese Individuls Seeking Weight Reduction Adm Gilden Tsi 1, Thoms A. Wdden 1, Dvid B. Srwer 1, Robert I. Berkowitz 1, Leslie G. Womble 1, Louise A. Hesson 1, Suznne Pheln 2 nd Rebecc Rothmn 1 bckground: No previous reserch hs exmined the ssocition between metbolic syndrome (MetSyn) nd helth-relted qulity of life (HRQoL) using stndrd criteri for defining MetSyn. We hypothesized tht MetSyn would be ssocited with lower HRQoL on mesures of physicl nd mentl helth. Methods nd Procedures: Prticipnts were 361 individuls in two rndomized weight loss trils. MetSyn ws defined by the Ntionl Cholesterol Eduction Pnel criteri. The Medicl Outcomes Study, Short Form-36 (SF-36) ws used to ssess HRQoL. Differences in HRQoL nd in clinicl nd psychosocil chrcteristics were compred mong prticipnts with nd without MetSyn. Multiple regression ws used to determine predictors of HRQoL. Results: MetSyn ws ssocited with lower scores on the physicl function nd generl helth subscles of the SF-36 nd on the physicl component summry (PCS) score. This ssocition remined fter controlling for ge or depression but ws eliminted by controlling for BMI. MetSyn ws not ssocited with lower mentl qulity of life, higher depression score, tobcco or lcohol use, or higher rte of psychosocil stressors. Discussion: Individuls with MetSyn reported lower HRQoL. This ppered to be n effect of incresed weight, rther thn unique effect of MetSyn. Lrger studies re needed to ssess whether MetSyn my hve n independent effect on HRQoL. IntroductIon Helth Orgniztion (10,11). In ddition, these studies did Metbolic syndrome (MetSyn) is ssocited with n incresed not exmine whether differences in qulity of life tht were risk for developing type 2 dibetes, s well s crdiovsculr ttributed to MetSyn my, in fct, hve been ttributble to the disese (1 3). Insulin resistnce is thought to lie t the hert higher BMI of persons with the syndrome. of the syndrome, which is dignosed when ptients meet t In the present study, we used the Medicl Outcomes Study, lest three of the following five criteri: elevted wist circum- Short Form-36 (SF-36) (12,13) to determine whether individference (>40 inches for men, >35 inches for women); high uls with metbolic syndrome hd lower scores on the physitriglycerides (>150 mg/dl); reduced high-density lipoprotein cl helth nd mentl helth subscles of the instrument. The cholesterol (<40 mg/dl for men, <50 mg/dl for women); high physicl helth subscles include those tht mesure physicl fsting glucose (>100 mg/dl); nd elevted blood pressure function (i.e., degree of limittion in performing ctivities of (>130/85 mm Hg) (4). dily living), physicl role (i.e., limittions in dily ctivi- Some investigtors believe tht metbolic syndrome is lso ties due to physicl helth), bodily pin (i.e., limittions in ssocited with n incresed risk for psychitric comorbidity, dily ctivities due to pin), nd generl helth (i.e., selfstress, nd impired helth-relted qulity of life (HRQoL) evlution of overll helth). The mentl helth subscles (5 8). For exmple, two previous studies hve reported tht include those tht mesure vitlity (i.e., energy nd ftigue), individuls with metbolic syndrome hd reduced qulity of socil functioning (i.e., limittions in socil ctivities due life, principlly in the re of physicl function (7,9). In these to physicl or emotionl helth), emotionl role (i.e., limitwo studies, however, unconventionl criteri were used to ttions in usul role ctivities due to emotionl problems), define MetSyn, s compred to the criteri developed by the nd generl mentl helth (i.e., psychologicl distress nd Ntionl Cholesterol Eduction Progrm (4) or by the World well-being). We lso exmined whether the hypothesized 1 Center for Weight nd Eting Disorders, University of Pennsylvni School of Medicine, Phildelphi, Pennsylvni, USA; 2 Weight Control nd Dibetes Reserch Center, The Mirim Hospitl, Brown Medicl School, Providence, Rhode Islnd, USA.

2 ssocition between MetSyn nd lower HRQoL could be explined, in prt, by higher BMI or by higher rte of psychosocil complictions (e.g., depression, history of mentl illness, lcohol nd tobcco buse, nd stress) mong those with the syndrome. Methods And procedures prticipnts Prticipnts were 404 overweight nd obese individuls who took prt in one of two rndomized weight control trils tht hve been reported previously (14,15). Prticipnts in both studies were required to hve BMI of kg/m 2 nd were excluded if they hd significnt medicl or psychitric comorbidities, described previously (15). These included uncontrolled hypertension (>140/90 mm Hg), types 1 or 2 dibetes, or the use of medictions known to cuse long-term chnges in weight. The presence of MetSyn ws ssessed using the Ntionl Cholesterol Eduction Progrm criteri (4). Prticipnts who took medictions for hypertension or hypercholesterolemi were counted s meeting the blood pressure nd triglyceride criteri for metbolic syndrome. outcomes mesures SF-36. The SF-36 ws used to ssess HRQoL. This mesure includes eight subscles, ll of which re used to derive summry mesure of physicl helth nd summry mesure of mentl helth (12,13). Higher scores, both on the eight subscles nd the two summry mesures, indicte better functioning. Depression. Symptoms of depression were ssessed using the Beck Depression Inventory (BDI-II), the stndrd mesure for depression in mentl helth (16). Scores rnge from 0 to 63, with higher vlues indictive of greter symptoms of depression. Scores of 0 13 re considered miniml (i.e., in the norml rnge). Prticipnts lso reported whether they hd history of mentl helth problems, s ssessed by the Weight nd Lifestyle Inventory (17). Lifestyle hbits. Lifestyle hbits, including smoking nd lcohol intke, were lso ssessed with the Weight nd Lifestyle Inventory (17). This questionnire hs good relibility for these items (18). The Weight nd Lifestyle Inventory ws lso used to identify ongoing sources of stress, including those relted to work, intimte reltionships, nd legl/finncil troubles. Prticipnts responded yes or no to the presence of ech of eight psychosocil stressors, s described previously (17). sttisticl nlysis Full dt concerning MetSyn nd qulity of life were vilble for 361 of the originl 404 prticipnts. Individuls who were not included in the nlysis dt set did not differ in ge, weight, BMI, eduction, or ethnicity from the 361 persons for whom full dt were vilble. If prticipnt hd missing dt on one or more components of MetSyn but met t lest three criteri, the individul ws designted s hving the syndrome. Differences in weight nd in other chrcteristics between prticipnts with nd without MetSyn were compred using t-tests for continuous vribles nd chi-squre tests for ctegoricl vribles. Similr nlyses were used to compre individuls with nd without MetSyn on: (i) the eight subscles of the SF-36; (ii) symptoms of depression; (iii) lifestyle hbits; nd (iv) psychosocil stressors. Zero-order correltions were used to estimte the strength of ssocition between HRQoL nd single vribles of interest. Multivrible regression ws then used to ssess the totl vrince in HRQoL explined by ll predictor vribles. All nlyses were conducted using Stt softwre, version 9.2 (Stt Corportion, College Sttion, TX). A P vlue <0.05 ws considered significnt for ll nlyses. results Metbolic syndrome Prticipnts with MetSyn hd significntly greter ge (P = 0.002), height (P < 0.001), weight (P < 0.001), nd BMI (P < 0.001) thn those without the syndrome (Tble 1). A higher percentge of individuls with MetSyn were white (P = 0.02) nd mle (P < 0.001). As expected, prticipnts with MetSyn lso hd significntly higher blood pressure, higher fsting glucose nd insulin, higher triglycerides, nd lower high-density lipoprotein cholesterol thn did those without MetSyn (P < for ll comprisons). Low-density lipoprotein cholesterol levels did not differ significntly between the two groups (Tble 1). Qulity of life Comprisons of HRQoL between prticipnts with nd without MetSyn re shown in Tble 2. Individuls with MetSyn hd significntly lower scores on two of the eight subscles of the tble 1 Bseline chrcteristics of prticipnts with nd without metbolic syndrome, mong individuls seeking weight reduction No metbolic Metbolic syndrome syndrome (n = 226) (n = 135) P vlue Gender, number (%) Femle 190 (84.1%) 82 (60.7%) <0.001 Mle 36 (15.9%) 53 (39.3%) Ethnicity White 167 (73.9%) 113 (83.7%) 0.02 Africn Americn 56 (24.8%) 20 (14.8%) Other b 3 (1.3%) 2 (1.5%) Age (yer) 44.9 ± ± Eduction (yer) 15.6 ± ± Weight (kg) 96.7 ± ± 18.6 <0.001 Height (cm) ± ± 10.1 <0.001 BMI (kg/m 2 ) 34.7 ± ± 4.2 <0.001 Wist (cm) 41.5 ± ± 5.1 <0.001 Low-density ± ± lipoprotein (mg/dl) High-density 61.2 ± ± 11.0 <0.001 lipoprotein (mg/dl) Triglycerides (mg/dl) ± ± <0.001 Systolic blood ± ± 14.5 <0.001 pressure (mm Hg) Distolic blood 68.7 ± ± 10.0 <0.001 pressure (mm Hg) Glucose (mg/dl) 91.4 ± ± 15.0 <0.001 Insulin (μu/ml) 12.9 ± ± 15.8 <0.001 Insulin resistnce c 2.9 ± ± 4.9 <0.001 Vlues re men ± s.d. with the exception of gender nd ethnicity, which re shown s n (%). b Other = Asin Americn or Ltino. c Insulin resistnce ws determined using the homeostsis model of insulin resistnce (26). Scores rnge from 0 to 15, with higher scores indicting greter insulin resistnce, nd re clculted s the product of the fsting plsm insulin level (in microunits per milliliter) nd the fsting plsm glucose level (in millimoles/liter), divided by 22.5.

3 SF-36. These were, physicl functioning (P = 0.021) nd gen- Depression Inventory scores or in the percentge of ptients erl helth (P = 0.007). Prticipnts with MetSyn lso scored who reported history of mentl helth problems or of lcosignificntly lower on the physicl component summry (PCS) hol or tobcco use. There lso were no significnt differences score (P = 0.013). No differences were observed between those between groups in the number of psychosocil stressors with nd without MetSyn on ny of the four subscles of the (Tble 3). SF-36 tht ssessed dimensions of mentl helth or in the mentl component summry score (Tble 2). correltions nd regression nlyses Correltion nd regression nlyses re shown in Tbles 4 psychosocil sttus nd lifestyle hbits nd 5 for the PCS score of the SF-36. In univrible nly- The psychosocil chrcteristics of prticipnts with nd ses, lower vlues on the PCS score were ssocited with the without MetSyn re shown in Tble 3. No significnt dif- presence of MetSyn, higher BMI vlues nd depression scores, ferences were observed between the two groups in Beck nd with higher ge. By contrst, there ws no ssocition between the PCS score nd yers of eduction, gender, ethnictble 2 Bseline sf-36 scores for prticipnts with nd ity, lcohol intke, smoking sttus, or psychosocil stressors without metbolic syndrome mong individuls seeking (Tble 4). weight reduction A forwrd step-wise regression nlysis ws conducted No metbolic Metbolic using the four vribles tht hd the strongest ssocition syndrome syndrome (n = 226) (n = 135) P vlue with the PCS score derived from univrible nlysis. They Physicl functioning 80.6 ± ± tble 4 univrible correltion of the physicl component Role physicl 82.2 ± ± summry (pcs) score of the sf-36 with demogrphic nd Bodily pin 72.8 ± ± psychosocil vribles Generl helth 71.3 ± ± Correltion Vrible coefficient P vlue Vitlity 49.6 ± ± BMI 0.27 <0.001 Socil function 85.4 ± ± Depression score 0.23 <0.001 Role emotionl 75.5 ± ± Metbolic syndrome Mentl helth 74.7 ± ± Age Physicl component 49.1 ± ± summry Yers of eduction Mentl component 48.6 ± ± summry SF-36, Medicl Outcomes Study, Short Form-36. Vlues re men ± s.d. tble 3 psychosocil chrcteristics nd lifestyle hbits of prticipnts with nd without metbolic syndrome mong individuls seeking weight reduction Ever smoker Drinks per week Number of stressors Ethnicity Gender SF-36, Medicl Outcomes Study, Short Form-36. Beck Depression Inventory. No metbolic Metbolic syndrome b syndrome c P vlue tble 5 Vrince in the physicl component summry (pcs) Beck Depression Inventory 7.7 ± ± score ccounted for by BMI, depression score, ge, nd the History of mentl helth 58 (26.0%) 33 (24.8%) 0.80 metbolic syndrome, s determined by forwrd step-wise problems, number (%) regression Psychosocil stressors, 1.6 ± ± Vrible Cumultive R 2 P vlue totl number Full model Work, number (%) 116 (51.8%) 65 (48.9%) 0.59 BMI 0.07 <0.001 Helth, number (%) 57 (25.4%) 32 (24.1%) 0.77 Depression score 0.11 <0.001 Intimte reltionships, 49 (21.9%) 20 (15.0%) 0.11 Age 0.15 <0.001 number (%) Metbolic syndrome Legl/finncil, number (%) 53 (23.7%) 25 (18.8%) 0.28 Current smoker, number (%) 9 (4.0%) 4 (3.0%) 0.77 Prtil model #1 BMI 0.07 <0.001 Ever smoker, number (%) 106 (47.3%) 69 (51.9%) 0.41 Age Alcoholic drinks per week, 2.3 ± ± Metbolic syndrome number Prtil model #2 BMI 0.07 <0.001 Vlues re men ± s.d. for depression score, number of stressors, nd drinks Metbolic syndrome per week; nd n (%) for other vribles. b n rnges from 219 to 224. c n rnges from 131 to 133. Beck Depression Inventory.

4 were entered into the regression ccording to the strength of their ssocition BMI, depression score, ge, nd MetSyn. As shown in Tble 5, three vribles BMI, depression score, nd ge explined 15% of the vrince in the PCS score. MetSyn did not contribute significntly to the vrince explined fter ccounting for these three vribles. Secondry nlyses showed tht the effect of MetSyn ws eliminted by controlling for BMI lone (Tble 5). discussion This study found tht MetSyn ws ssocited with lower HRQoL on two of the physicl subscles of the SF-36. These were physicl function (i.e., limittions in dily ctivities due to physicl helth) nd generl helth (i.e, self-reported overll helth sttus). In ddition, prticipnts with MetSyn scored significntly lower on the PCS score thn did persons without the syndrome. By contrst, no ssocition ws observed between MetSyn nd the mentl component summry score or ny of the SF-36 subscles relted to mentl helth. There lso ws no ssocition between MetSyn nd symptoms of depression, lcohol or tobcco use, or psychosocil stressors. Prticipnts in the present study who hd MetSyn hd significntly higher BMI thn those without the syndrome (37.4 kg/m 2 vs kg/m 2, respectively). Correltion nlyses showed tht both BMI nd MetSyn were ssocited with lower PCS score. Results of multiple regression nlysis, however, showed tht MetSyn did not ccount for significnt mount of the vrince in PCS scores fter controlling for BMI. Thus, the reduced HRQoL in prticipnts with MetSyn ppered to be relted to their greter BMI, rther thn to MetSyn per se. Numerous studies hve shown tht higher BMI is ssocited with lower HRQoL (19 25). Two previous studies reported tht MetSyn ws ssocited with reduced HRQoL (7,9). However, neither of these investigtions controlled for the effect of BMI. In ddition, neither of these studies used stndrdized criteri to define MetSyn, such s the criteri used by the Ntionl Cholesterol Eduction Pnel (4) or World Helth Orgniztion (10,11). A third study found lower SF-36 scores t bseline for ll eight domins mong popultion of surgiclly treted obese ptients, but no ssocition of lower qulity of life with insulin resistnce (19). The other criteri for MetSyn were not exmined. The present study hd severl limittions. First, ptients with type 2 dibetes were excluded from both of the clinicl trils used for the nlysis. Obese individuls with type 2 dibetes re likely to meet the criteri for MetSyn nd my experience lower HRQoL thn persons with the syndrome who do not hve dibetes. Second, our smple consisted principlly of persons from middle- to upper-middle socioeconomic bckgrounds (men eduction of 15.6 yers in the present nlysis). Higher socioeconomic sttus my protect obese individuls from the potentil dverse helth nd psychosocil consequences of MetSyn. 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