Journal of Choce Modellng, 2(1), pp. 51-64 www.jocm.org.uk Offsettng Behavor n educng Hgh Cholesterol: Substtuton of Medcaton for Det and Lfestyle Changes Lsa Mancno 1,* Fred Kuchler 1, ¹Economc esearch Servce, USDA, 1800 M Street, N 4057, Washngton, DC, USA eceved 14 September 2007, revsed verson receved 15 November 2008, accepted 13 February 2009 Abstract Beng dagnosed wth a det-related health condton lke hgh blood cholesterol mght compel an ndvdual to choose a healther det, thereby reducng dsease rsks. Addng the opton of medcaton, lke statns, makes the drecton of detqualty choces theoretcally ambguous. Ths study estmates how detary qualty correlates wth hgh cholesterol dagnoses and medcne use. esults ndcate that ndvduals dagnosed wth hgh cholesterol consume less cholesterol, fat, and saturated fat, and smoke less. However, usng cholesterol-lowerng drugs s correlated wth ncreased fat and saturated fat ntake, and larger wast sze, after accountng for the endogenety of choosng to use medcne. Fndngs hghlght the nelastcty of det choces. Keywords: offsettng behavour, cholesterol, det, medcaton 1 Introducton Worldwde, nearly 1.6 bllon adults were overweght and over 400 mllon were obese n 2005. By 2015, t s projected that these numbers wll rse to 2.3 bllon overweght and 700 mllon obese (World Health Organzaton, 2006). Such trends are troublng, as scentfc evdence ndcates obesty s assocated wth ncreased rsk of premature death, type II dabetes, heart dsease, stroke, hypertenson, gallbladder dsease, osteoarthrts, and many other malades (U.S. Department of Health and Human Servces, Publc Health Servce, Offce of the Surgeon General, 2001). Ths wdespread prevalence of obesty and det-related llnesses begs the queston why so many people are puttng themselves at rsk of serous llnesses. * Correspondng author, T: +202 694-5563, F: +202 694-5688, Lmancno@ers.usda.gov T: +202 694-5468, F: +202 694-5688, fkuchler@ers.usda.gov
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 The problem posed by many behavours that jeopardze health s that such behavour s tself often enjoyable. Whle the rsks of smokng are well-known, the satsfacton from ncotne makes t hard for many to break the habt. And though a det low n salt, cholesterol and saturated fat may promote cardovascular ftness, many choose taste and convenence over long-term health. The enjoyment of such rsky behavours concevably could have a major mpact on the realzed benefts from medcal advances, safety enhancements to consumer goods or government-mandated safety regulatons because ndvduals could respond by makng rsker choces (offsettng behavour), thus attenuatng the drect health benefts of these mprovements. The queston addressed n ths study s whether or not technologcal change nduces rsky choces for chronc health condtons that are manageable wth det and lfestyle choces. We estmate the extent to whch people dagnosed wth hgh cholesterol manage the potental health rsks by changng ther det and how much they compromse det qualty when they also use cholesterol-lowerng statn drugs. Thus for ths study, we develop a theoretcal model to show that f consumers treat det and medcaton as substtutes n producng good health, consumers are unlkely to realze all the health benefts possble from det and medcaton. For emprcal support of our hypotheses, we use data from the Natonal Health and Nutrton Examnaton Survey (NHANES) 1999-2000, 2001-2002, and 2003-2004, whch contan detaled nformaton on detary ntake, medcal condtons and whether an ndvdual takes medcaton for such condtons. These data are used to estmate how dfferences n detary qualty correlate wth whether or not an ndvdual has been dagnosed wth hgh cholesterol, and whether or not an ndvdual uses medcaton to manage hs or her health condton. 2 Background Peltzman (1975) ntated emprcal work on offsettng behavour, demonstratng that U.S. government-mandated automoble safety equpment had lttle mpact on hghway safety. Mandated safety equpment probably made cars safer for drvers and passengers, but smultaneously reduced the cost of reckless speed. Drvers responded by rasng ther drvng ntensty, leadng to more accdents. A vast lterature estmatng the magntude of offsettng behavour and deaths and njures followed Peltzman s fndngs. (See Hause (2006), for fndngs related to traffc, workplace, and consumer product accdents). Concevably, mprovements n drug treatments could nduce a lullng effect, (Vscus, 1984). Kahn (1999) nvestgated a problem smlar to ours the det and lfestyle choces dabetcs made over a perod n whch drugs that help control blood sugar dramatcally mproved. Hs concern was that mproved drugs could have made dabetcs falsely thnk the drugs solved ther health problems, reducng adherence to the det regmes recommended to manage dabetes. The undesrable result would be addtonal complcatons of dabetes heart dsease, stroke, amputatons, blndness, and renal falure. Hs emprcal results showed no sgnfcant evdence of offsettng behavour, but ncluded the use of medcaton as an exogenous, explanatory varable. For modellng rsky choces lke drvng ntensty, ths s a reasonable assumpton, as safety equpment mandated by government regulaton s arguably exogenous. And whle usng medcaton to treat det-related llnesses can be vewed as a knd of safety equpment, pharmaceutcal use s often a choce nfluenced by many of the same factors that nfluence det qualty. As such, treatng pharmaceutcal use as 52
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 an exogenous varable wll bas ts estmated effect. If an overall concern for health s postvely correlated wth the probablty of takng medcaton to mprove health, then any estmator that does not account for the smultaneous nature of these choces wll upwardly bas the estmated effect of takng medcaton. The other parameter estmates wll be based as well. For ths study, we focus on hgh blood cholesterol, whch s a major rsk factor for heart dsease (U.S. Department of Health and Human Servces, Centers for Dsease Control and Preventon, 2007). Coronary heart dsease s the leadng cause of morbdty and mortalty n the Unted States, estmated to cause 481,000 deaths each year and requre 11.8 mllon hosptal days of care per year. It s the leadng cause of dsablty adjusted lfe years and s second only to njures as a cause of lfe-years lost (Gross et al., 1999). However, hgh blood cholesterol s a modfable rsk factor. Detary changes, ncreased physcal actvty, weght control, drug therapy, or a combnaton of these have been shown to lower cholesterol levels (U.S. Department of Health and Human Servces, Centers for Dsease Control and Preventon, 2007). Lowerng cholesterol and other fats n the blood may help prevent medcal problems caused by cholesterol cloggng the blood vessels (Mller and Stagntt, 2005) and substantally reduce health rsks: a 10 percent decrease n total blood cholesterol can reduce the ncdence of heart dsease by as much as 30 percent (U.S. Department of Health and Human Servces, Centers for Dsease Control and Preventon, 2007). In recent years, ndvduals have demonstrated a growng nterest n drug therapy as a means of lowerng blood cholesterol. Whle there have been cholesterol-reducng drug therapes avalable for many years, the statn drugs are more effectve at reducng cholesterol 1 than older drugs (Pgnone et al., 2001). anked by expendtures, the top two drugs n 2003 were cholesterol-reducng agents: Lptor (Atorvastatn calcum) and Zocor (Smvastatn) (U.S. Department of Health and Human Servces, Agency for Healthcare esearch and Qualty, 2006). 3 Theoretcal and Emprcal Model One response to a dagnoss of hgh blood cholesterol could be to strctly follow doctor s orders. However, desres for good health may compete aganst desres for famlar dets and lfestyle. These det and lfestyle choces may be condtoned by a lfetme of habt as well as by famly and communty tradtons. Thus, medcaton may be a substtute for det and lfestyle changes as a means to reduce health rsks because t lowers the health cost (ncreased probablty of an adverse outcome) of falng to make det and lfestyle changes. In ths case, some offsettng behavour s almost certan; the mportant queston for forecastng a health outcome s how much offsettng behavour wll occur? If the protectve effect of medcaton s assumed large whle the pull of the famlar det and lfestyle s strong, major det and lfestyle changes are unlkely. 1 There are several patterns of blood lpds that are mportant rsk factors for coronary heart dsease. These nclude elevated total cholesterol (usually wth a threshold of 240mg/dl), elevated low-densty lpoproten cholesterol (LDL), and low levels of hgh-densty lpoproten cholesterol (HDL) (Pgnone et al., 2001). For ease of exposton, we refer to ths class of health condtons as hgh cholesterol and drug therapy as cholesterol-reducng. 53
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 For a more precse understandng of how consumers wll respond to a dagnoss of hgh blood cholesterol, we employ a straghtforward utlty maxmzaton problem. We assume ndvduals gan utlty from rsky behavours (), ther own health (H) and all other goods (C). We defne H as a perceved health producton functon and assume that ndvduals manage health through behavours and medcaton (M). For smplcty, rsky behavours over whch utlty s defned are selectng a nutrtonally poor det and havng a sedentary lfestyle. Offsettng behavour flows drectly from utlty maxmzng behavour. As long as good health enters the utlty functon, the health-compromsng (undesrable) attrbutes of rsky behavours also nfluence the utlty maxmzaton. Also, how hghly an ndvdual assesses hs current level of health s drven by η, a parameter that represents medcal evdence of a current health condton. For example, someone who was told that he had hgh blood cholesterol would assess hs health at a lower level than before learnng ths news. Thus, there s an nverse relatonshp between H and η. Other goods (C) are assumed to have no drect mpact on health. Maxmzng utlty subject to the ncome constrant and to the health producton functon can be wrtten n standard form as max U(, H(, M; ), C ) s.. t P P M C I M (1) where I s ncome, P and P M are the prces for rsky behavours and medcaton, and for smplcty, the prce of all other goods, C, s defned as the numerare. Frst order condtons mply the followng equalty: U U H H P. (2) U H P H M M That s, the margnal rate of substtuton between rsky behavours and pharmaceutcals that offset the health cost of rsky behavours s equal to the prce rato. The margnal utlty of rsky behavours s a net concept as t ncludes the drect benefts as well as the health cost. ewrtng equaton (2) as PM F U H ( U U H ) 0 H M H (3) P and nvokng the mplct functon rule yelds a relaton between rsky behavour and perceved health status. PM U H H U H ( U H U H H U H ) H M M HH H H HH F P (4) F PM 2 U H H U ( U 2 U H U H U ( H ) ) H M M H H H HH P 54
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Our goal s to sgn the dervatve the change n rsky behavour gven bad health news for a typcal ndvdual, not all mathematcally possble utlty and producton functons. We make conventonal assumptons that U 0 and U, H 0 for, H, C. That s, the margnal utltes are postve, and utlty and producton functons are concave. The margnal product of medcne s postve, but rsky behavours that brng enjoyment are defned to be unhealthy and nformaton about health s assumed to be bad news, reducng perceved health status. (5) H 0 for j M and j H 0 for j,. j (6) Conventonal utlty and producton functon assumptons, however, are not suffcent to sgn the dervatve. In addton, we assume that UH UH 0. That s, bad behavour can be more rewardng when n better health. The equalty also allows for the possblty that the rewards from bad behavour are ndependent of health status. We assume H 0, H 0, H H 0. Medcne becomes more M M M mportant to health when health news s bad (or does not change), rsky behavours compromse health more (or equally) when health news s bad, and the effcacy of medcne s ndependent of poor det and lfestyle choces. For example, we assume that a statn drug s margnal mpact on health s unaffected by one s level of physcal actvty. Under these condtons, s negatve, ndcatng that the net effect of bad health news s to reduce rsky behavours that compromse health. Indvduals wll adjust to bad health news by makng healther det and lfestyle choces. To determne the mpact of medcaton on rsky behavours, we use the followng relaton between pharmaceutcal use and rsky behavour: 2 PM U H U ( H ) ( U H U H H U H ) H MM HH M H M H M HH M F P M. (7) M F PM 2 U H H U ( U 2 U H U H U ( H ) ) H M M H H H HH P Under the same condtons mposed on partal dervatves and cross partals, s M postve. In effect, medcne makes t easer to return to rsky behavours that compromse health. The mpact of makng health benefts possble from pharmaceutcals means that many wll forego some, f not all, of the possble health benefts. Some ndvduals wll fnd they mprove ther overall well-beng by takng medcaton whle also choosng dets and lfestyles that are less healthy than they would choose f they had to rely on det and lfestyle alone to manage a det-related dsease. 55
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Ths analyss of partal and cross partal dervatves yelds three hypotheses that can be tested emprcally: There s a negatve relatonshp between beng made aware of a health condton, such as hgh blood cholesterol, and specfc behavours, such as choosng to eat an unhealthy det; There s a postve relatonshp between takng medcaton for a health condton and these same rsky behavours; and The effect of medcaton on ncreasng rsky behavours may offset the reductve effect of better health awareness. Emprcally, our model suggests that an ndvdual s chosen level of rsky behavours ) can be modelled as a functon of ncome, prces, and health status ( H ), whch s ( determned by behavours, awareness of a health condton ( ), and use of prescrbed medcaton ( M ). Ths specfcaton llumnates the smultaneous nature of behavoural choces, medcaton and health status. The emprcal model can be wrtten as: where X s a vector of exogenous explanatory varables that relate to ndvdual behavoural choces, ndcates whether or not an ndvdual s aware of a specfc health condton, and e s a random dsturbance term. Among ndvduals who have been dagnosed wth a health-condton, ther behavoural choces can be modelled as follows where M ndcates whether or not an ndvdual takes medcaton for ths condton and Z s a vector of exogenous explanatory varables relatng to whether or not an ' X e (8) X M e ', D M Z ndvdual chooses to manage hs health condton through medcaton, and s a random dsturbance term. An estmaton approach that does not explctly address that ndvduals wth a health condton can use both medcaton and behavoural modfcaton to manage health wll produce based estmates of the relatonshp between explanatory varables and observed behavours. Thus, among ndvduals dagnosed wth hgh cholesterol, we estmate each behavoural choce equaton smultaneously wth a treatment effect. In the frst equaton, we run a probt regresson to estmate whether an ndvdual chooses to manage health va medcaton. In the second equaton, we estmate how the choce to take medcaton correlates wth dfferences n det and actvty choces recommended to control levels of cholesterol. Followng the estmaton strategy of Lakdawalla et al. (2006), to allow for correlaton between use of medcaton and rsky 56 (9a) (9b)
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 behavours, we assume that the errors e and are correlated and jontly dstrbuted as bvarate normal. We use maxmum lkelhood to estmate ths jont model. To obtan robust varance estmates, we use the treatreg command n STATA 9.0, controllng for survey sample weghts and nter-strata varaton. 4 Data Ths study uses recent data sets from the Natonal Health and Nutrton Examnaton Survey 1999-2000, 2001-2002, and 2003-2004 (for smplcty NHANES 1999-2004). The NHANES data have been collected annually through the Centers for Dsease Control and Preventon va the Natonal Center for Health Statstcs snce 1999. Each year approxmately 5,000 cvlan, non-nsttutonalsed persons n the Unted States receve a thorough medcal examnaton, provde a 24-hour detary recall, and answer questons related to health behavours, such as detng, physcal actvty, alcohol consumpton, and cgarette smokng. Ths survey s desgned to be natonally representatve and over-samples Afrcan-Amercans, Mexcan-Amercans and ndvduals wth low ncome (Unted States Department of Health and Human Servces, Centers for Dsease Control and Preventon, Natonal Center for Health Statstcs, 2006). We lmt our analyss to adults, aged twenty and older. Indvduals under the age of 20 were not asked f they were dagnosed wth hgh cholesterol. We also exclude pregnant and lactatng women from our analyss snce ther detary needs dffer sgnfcantly from the rest of the populaton. In total, our sample ncludes observatons on 11,446 ndvduals. In general, ndvduals wth hgh cholesterol are nstructed to choose a det that s low n cholesterol, fat, and saturated fat. They are told to qut smokng and mantan a healthy bodyweght. We therefore created several dependent varables based on these recommendatons (Table 1). For cholesterol, fat, and saturated fat, the dependent varable s total daly consumpton of each nutrent per day dvded by that ndvdual s total daly energy ntake (calculated from 24-hour detary recall reports). For cgarettes, the dependent varable s constructed as the number of cgarettes consumed on average. As a measure of excess bodyweght, we use an ndvdual s measured wast crcumference relatve to the gender specfc overweght classfcaton 88 centmetres for women and 102 centmetres for men (U.S. Department of Health and Human Servces, Natonal Insttutes of Health, Natonal Insttute of Dabetes and Dgestve and Kdney Dseases, 2004). We chose ths measure over body mass ndex (BMI), or weght adjusted for heght, because BMI measures do not dstngush between muscle and total fat. The explanatory varables used n our econometrc estmaton are also descrbed n Table 1. We present the analyss of ncome dfferences n terms of a households ncome-to-poverty rato (PI) the rato of a household s ncome relatve to the poverty threshold, gven the sze of a famly. We also control for an ndvdual s level of educaton (educaton up to and ncludng hgh school or more than hgh school) because ths varable s hghly predctve of ncome and health knowledge. 2 2 Smlar to other natonal surveys on detary ntake, NHANES does not collect nformaton on food prces respondents pay or ther food expendtures. 57
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Table 1: Summary Statstcs Varable Name Defnton and unts Mean Std. Err. Cholesterol Dependent varables Cholesterol consumpton adjusted for calorc ntake: 100 daly cholesterol ntake (mg)/daly calorc ntake 12.93 0.19 Total fat Total fat share of calores: 100 9 daly fat ntake (g)/daly calorc ntake 33.50 0.21 Saturated fat Saturated fat share of calores: 100 9 daly saturated fat ntake (g)/daly calorc ntake 10.92 0.10 Cgarettes Average daly cgarette ntake 3.07 0.20 Wast ato of wast crcumference (cm) to gender- specfc overweght classfcaton (88 cm for women, 102 cm for men) Explanatory varables for rsky behavors 1.00 0.00 PI Poverty Index ato: Household ncome/poverty lne for household sze 3.29 0.06 More than hgh school 1 f ndvdual went to school beyond hgh school; zero otherwse 0.64 0.01 Age Age n years 44.41 0.41 Female 1 f female; zero otherwse 0.48 0.01 Black, Non-Hspanc 1 f black, non-hspanc; 0 otherwse 0.09 0.01 Hspanc 1 f Hspanc; 0 otherwse 0.10 0.01 Other Ethncty 1 f other ethncty; 0 otherwse 0.04 0.01 Spansh 1 f Spansh s the prmary language spoken at home; zero otherwse 0.04 0.01 Other language Other health condton 1 f nether Englsh nor Spansh are the prmary languages spoken at home; zero otherwse 1 f ndvdual has ever been dagnosed wth dabetes, heart falure, coronary heart dsease, heart attack, or stroke; zero otherwse 0.04 0.01 0.11 0.01 Dagnosed wth hgh cholesterol 1 f ndvdual has been dagnosed wth hgh cholesterol; zero otherwse 0.26 0.01 Undagnosed, but cholesterol hgh 1 f ndvdual has not been dagnosed wth hgh cholesterol, but LDL measures 160 mg/dl or above; zero otherwse 0.20 0.01 Treatment varable Medcaton 1 f takng cholesterol-lowerng medcaton; zero otherwse 0.10 0.01 Instrumental varables for medcaton Insurance 1 f ndvdual has health nsurance; zero otherwse 0.84 0.01 elatve wth 1 f relatve has hypertenson; zero otherwse 0.17 0.01 hypertenson elatve wth angna 1 f relatve has angna; zero otherwse 0.35 0.01 58
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 We account for systematc dfferences n food demand. For example, two ndvduals energy requrements may dffer because of age and gender. Cultural norms and level of acculturaton also have an nfluence on det characterstcs (Aldrch and Varyam, 2000). We attempt to capture these through an ndvdual s reported ethncty and whether a language other than Englsh s consdered to be the respondent s prmary language. Our theoretcal model predcts that beng aware of a health condton wll nfluence rsk-takng behavour. We defne an ndvdual as beng dagnosed wth hgh cholesterol f, n the questonnare regardng medcal condtons, the respondent ndcates that he or she has been dagnosed wth the condton. We nclude a dummy varable to ndcate f that ndvdual has any other health condtons, such as dabetes, coronary heart dsease, and angna or f that person had a past heart attack or stroke, as that could cause hm to change rsky behavours. We nclude a varable for ndvduals who ndcate that they have not been dagnosed wth hgh cholesterol but who have cholesterol levels that put them at rsk: levels of low densty lpd (LDL) cholesterol-- n excess of 160 mg/dl (Amercan Heart Assocaton, 2006). 3 To dentfy whether or not takng medcaton s correlated wth offsettng behavour, we control for the endogenety of ths choce by frst usng nstrumental varables to estmate the choce to take medcaton. One nstrument avalable n ths data set s whether or not any blood relatves have been dagnosed wth related health condtons. A blood relatve s health s arguably exogenous. We have very lttle control over whether a grandparent has a partcular health condton. However, such condtons may be hghly correlated wth our own health and level of health nformaton; our famly s health hstory s a strong predctor of our own health and watchng a famly member struggle wth ll health may provde motvaton to adopt healther practces. Thus, as nstruments, we use whether a respondent had any blood relatves who had been dagnosed wth ether angna or hypertenson. Prces of medcaton could also serve as addtonal nstruments (Park and Davs, 2001). As a proxy for prces, we use whether an ndvdual currently has health nsurance. 5 esults For each detary choce and behavour, we present the results of both the OLS and treatment effects estmatons for the entre NHANES sample (Table 2). These results can be nterpreted to answer whether beng dagnosed wth hgh cholesterol compels an ndvdual to reduce rsky behavours. We are also able to test whether the subset that have been dagnosed wth hgh blood cholesterol behave dfferently from those who have hgh blood cholesterol but have not been so dagnosed. Ths comparson s ndcatve of a behavoural change; past det detary choces of those dagnosed wth hgh cholesterol are lkely to be more smlar to those wth undagnosed hgh cholesterol than to those who have healthy blood cholesterol levels. 3 The Amercan Heart Assocaton webste states that LDL cholesterol level greatly affects rsk of heart attack and stroke, and s a better gauge of rsk than total blood cholesterol. 59
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Table 2: OLS Estmaton esults--effect of rsk awareness on rsk behavours Cholesterol Total Fat Saturated Fat Cgarettes Wast Estmated Estmated Estmated Estmated Estmated Explanatory varables Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Constant 8.37 (8.26) 26.98 (27.63) 10.34 (22.39) 4.92 (5.75) 68.14 (36.08) PI 0.03 (0.30) 0.11 (1.15) 0.00 (-0.07) -0.76 (-10.05) -0.8 (-5.63) More than hgh school -0.38 (-0.19) -0.07 (-0.21) -0.20 (-1.79) -2.5 (-10.63) -0.52 (-1.19) Age 0.19 (4.13) 0.25 (5.51) 0.04 (2.33) 0.29 (8.22) 0.73 (8.75) Age 2 0.00 (-3.00) 0.00 (-5.44) 0.00 (-2.82) 0.00 (-10.07) -0.01 (-8.11) Female -0.54 (-2.25) 0.48 (2.14) 0.08 (0.69) -1.19 (-5.33) 8.33 (16.41) Black, Non-Hspanc 1.93 (5.33) -0.63 (-1.75) -0.90 (-5.94) -2.49 (-8.23) 1.82 (3.57) Hspanc 1.49 (2.64) -0.61 (-1.49) -0.39 (-1.69) -2.94 (-6.87) -0.28 (-0.47) Other Ethncty -0.73 (-0.85) -2.82 (-2.31) -1.55 (-3.60) -2.05 (-3.61) -3.69 (-2.39) Spansh 0.51 (0.85) -3.30 (-5.29) -1.49 (-5.60) -2.94 (-7.32) -3.02 (-3.21) Other language 0.32 (0.42) -4.68 (-5.45) -1.58 (-4.48) -0.87 (-1.64) -5.6 (-4.31) Other health condton 1.47 (3.61) 0.5 (1.22) 0.14 (1.17) 1.24 (3.44) 6.08 (7.27) Undagnosed, but cholesterol hgh 0.44 (1.72) 0.43 (1.52) 0.42 (3.87) 1.42 (4.24) 6.96 (13.35) Dagnosed wth hgh cholesterol -0.33 (-1.03) -0.19 (-0.60) 0.01 (0.11) -0.12 (-0.44) 7.49 (10.16) Model Ft 2 0.02 0.04 0.03 0.09 0.19 N 10865 10865 10865 10820 10542 Can reject the hypothess that the coeffcents for dagnosed and undagnosed are equal usng 5% level of sgnfcance 60
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Tests for dfferences among coeffcents (α = 0.05) shows that compared to those who have hgh cholesterol but have not been dagnosed, those who have been dagnosed report a lesser degree of some rsky detary and lfestyle choces. On average, an ndvdual who consumed 2200 calores a day, ate approxmately 18 fewer mllgrams of cholesterol and about one less gram of saturated fat per day. The dagnosed also smoke sgnfcantly fewer cgarettes than those who have hgh levels of cholesterol that have not been dagnosed. These fndngs suggest that hgh blood cholesterol dagnoses do nduce behavoural changes the publc health communty recommends. Fndngs also ndcate no dfference n wast sze between the dagnosed and undagnosed. Thus, there s no evdence that wast sze s leadng physcans to test for hgh cholesterol. The man hypothess we want to test s that takng medcaton to manage health may cause an ndvdual to ncrease rsky behavour and may even offset the effect of ncreased awareness about the ll-health effects of rsky det and lfestyle choces (Table 3). Whle ntake of cholesterol and cgarette consumpton do not ncrease, our results ndcate that when people dagnosed wth hgh blood cholesterol choose medcaton they also consume hgher amounts of total fats and saturated fat. Agan assumng 2200 calores per day, an ndvdual who s dagnosed wth hgh cholesterol and takes medcaton for ths condton s estmated to eat roughly about 18 more grams of total fat and 12 more grams of saturated fat, respectvely. 4 Ther wast szes are also sgnfcantly hgher. Among those takng cholesterol reducng medcaton, wast crcumferences are estmated to be roughly 16 and 12 centmetres larger for men and women. Thus, these estmates far outwegh the reductons assocated wth beng dagnosed wth hgh cholesterol and provde evdence of offsettng behavour. Even when armed wth the knowledge of both how and why to adopt a healther lfestyle, many ndvduals choose not to make sgnfcant changes. Frst stage results show support for our hypothess that choosng to use medcaton s sgnfcantly and postvely correlated wth havng a relatve wth hypertenson. Use of medcaton s sgnfcantly and negatvely assocated wth educaton, beng a female, and havng any other health condton (Table 3). 6 Dscusson The worldwde ncreasng prevalence of overweght and obesty, along wth detrelated llnesses, suggests there must be somethng that compensates for acceptng such rsks. Such detary problems are becomng ncreasngly more common throughout developed countres. Gven these strong preferences, the task n store for the publc health communty changng ndvduals dets s extremely dffcult. Here, we offer a quanttatve perspectve on just how dffcult t wll be to realze a substantal mprovement. We focus attenton on the subset of consumers who have strong ncentves to choose a healthy det, those who have been told they have hgh levels of serum cholesterol, and show that they resst change. 4 There are many ways these extra nutrents can be derved from addtonal foods. Only a few ndvdual foods yeld these partcular proportons of fat and saturated fat. The extra fat and saturated fat could be realzed wth an extra 2 tablespoons of butter or an extra one-fourth cup of cream cheese every day. 61
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 Table 3: Treatment Effect Estmaton esults--effect of medcaton on rsk behavours Cholesterol Total Fat Saturated Fat Cgarettes Wast Estmated Estmated Estmated Estmated Estmated Explanatory varables Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Parameter (t-stat.) Constant 8.30 (2.12) 32.31 (11.49) 13.47 (10.88) -0.46 (-0.24) 79.11 (11.88) PI 0.01 (0.08) -0.18 (-0.87) -0.05 (-0.39) -0.76 (-4.23) -0.81 (-2.91) More than hgh school -0.63 (-0.99) 0.23 (0.40) 0.11 (0.31) -1.82 (-3.78) 0.07 (0.06) Age 0.22 (1.34) 0.04 (0.28) -0.11 (-2.08) 0.46 (5.64) 0.51 (1.79) Age 2 0.00 (-1.28) 0.00 (-1.12) 0.00 (0.84) 0.00 (-7.20) -0.01 (-2.62) Female -1.08 (-1.68) 1.11 (2.12) 0.62 (3.30) -0.42 (-1.06) 9.86 (11.21) Black, Non-Hspanc 2.50 (4.02) -1.02 (-1.51) -1.04 (-3.08) -2.47 (-4.91) 2.38 (1.88) Hspanc 2.08 (1.75) -1.78 (-2.12) -0.55 (-1.27) -1.76 (-2.40) -1.88 (-1.33) Other Ethncty 1.15 (0.59) -3.51 (-1.25) -2.48 (-2.37) -3.81 (-5.79) -8.90 (-2.25) Spansh -1.17 (-0.68) -4.74 (-4.32) -2.14 (-4.08) -3.54 (-5.65) -2.06 (-1.34) Other language -1.64 (-1.26) -4.01 (-2.53) -1.45 (-1.90) 1.05 (0.86) -2.91 (-0.82) Other health condton 1.00 (1.06) -1.36 (-1.37) -0.89 (-2.34) 2.13 (3.09) 0.99 (0.57) Medcaton-treatment effect 0.12 (0.04) 7.22 (1.93) 4.86 (4.47) -3.14 (-1.46) 14.33 (2.58) Treatment effect: Explanatory varables Constant -4.15 (-6.42) -4.13 (-6.25) -3.80 (-5.96) -4.27 (-6.32) -4.02 (-5.75) PI -0.03 (-1.02) -0.02 (-0.88) -0.02 (-0.65) -0.03 (-1.24) -0.03 (-1.14) More than hgh school -0.20 (-2.28) -0.22 (-2.44) -0.21 (-2.29) -0.20 (-2.26) -0.20 (-2.22) Age 0.12 (5.42) 0.12 (5.60) 0.11 (5.17) 0.12 (5.50) 0.11 (4.96) Age 2 0.00 (-4.39) 0.00 (-4.57) 0.00 (-4.23) 0.00 (-4.51) 0.00 (-4.00) Female -0.27 (-4.80) -0.27 (-4.62) -0.27 (-4.23) -0.26 (-4.43) -0.26 (-4.28) Black, Non-Hspanc -0.06 (-0.76) -0.09 (-1.03) -0.05 (-0.67) -0.05 (-0.66) -0.10 (-1.33) Hspanc 0.06 (0.42) 0.06 (0.43) 0.10 (0.70) 0.07 (0.44) 0.08 (0.49) Other Ethncty 0.31 (1.20) 0.24 (0.92) 0.25 (1.05) 0.30 (1.18) 0.27 (0.97) Spansh -0.12 (-0.62) -0.15 (-0.76) -0.16 (-0.87) -0.12 (-0.59) -0.14 (-0.72) Other language -0.16 (-0.81) -0.13 (-0.68) -0.16 (-0.81) -0.15 (-0.81) -0.15 (-0.74) Other health condton 0.59 (6.23) 0.60 (6.45) 0.59 (6.24) 0.59 (6.35) 0.63 (6.35) Insurance 0.40 (1.64) 0.35 (1.48) 0.34 (2.14) 0.48 (1.53) 0.41 (1.79) elatve wth angna 0.06 (0.74) 0.00 (-0.08) -0.01 (-0.05) 0.05 (0.61) 0.07 (0.92) elatve wth hypertenson 0.16 (2.17) 0.20 (3.11) 0.14 (2.14) 0.13 (1.61) 0.19 (2.86) Model Ft Correlaton (ρ) 0.04-0.46* -0.50** 0.17-0.44* N 3037 3037 3037 3034 2936 *Parameter estmated to be sgnfcant at the 10% level. **Parameter estmated to be sgnfcant at the 5% level. 62
L. Mancno & F. Kuchler, Journal of Choce Modellng, 2(1), pp. 51-64 We show that the threat of severe adverse health consequences can nduce sgnfcant mprovements n det qualty (mprovements from the perspectve of the publc health communty, not from consumers perspectves). Cgarette smokng and detary ntake of cholesterol, total fat, and saturated fat are lower for those whose physcans told them they have hgh cholesterol, compared to those wth undagnosed hgh cholesterol. But, some also choose to compromse det qualty. We fnd that detary ntake of cholesterol s unaffected by the decson to take cholesterol-lowerng medcaton. However, for those takng cholesterol-lowerng medcaton, dets are hgher n total fats and n saturated fats than are dets of those wth unmedcated hgh cholesterol. The wast crcumference of those on medcaton s also larger, although some of the ncrease may be assocated wth reduced cgarette consumpton. The ncreased detary ntake of fat and saturated fat, along wth ncreased wast sze are tellng evdence of offsettng behavour, as medcaton lowers the health prce of unhealthy choces. Ths suggests that, f lfe-threatenng llnesses are not suffcent motvaton for ndvduals to mprove ther dets and health behavours, general publc health admontons to the populaton at large are unlkely to have much mpact. The remanng polcy queston s whether those wth hgh blood cholesterol are fully nformed about the health benefts of medcaton. If ndvduals over assess the effcacy of medcatons, ther utlty maxmzng choces could lead to dets and lfestyles that are even worse (for health) than the dets and lfestyles they chose before dscoverng ther compromsed health condton. In that case, the publc health communty could consder focusng attenton on accurately portrayng the health benefts of medcaton. Acknowledgements We would lke to thank the anonymous revewers for ther detaled comments on the paper. The opnons expressed here are those of the authors and not necessarly those of the U.S. Department of Agrculture. eferences Aldrch, L., Varyam, J. N. 2000. Acculturaton erodes the det qualty of U.S. hspancs. Food evew 23 (1), 51-55. Amercan Heart Assocaton, 2006. What are healthy levels of cholesterol? http://www.amercanheart.org/presenter.jhtml?dentfer=183. Frosch, D. L., Krueger, P. M., Hornk,. C., Cronholm, P. F., Barg, F. K., 2007. Creatng demand for prescrpton drugs: A content analyss of televson drect-to-consumer advertsng. Annals of Famly Medcne 5 (1), 6-13. Gross, C. P., Anderson, G. F. Powe, N.., 1999. The relaton between fundng by the Natonal Insttutes of Health and the burden of dsease. New England Journal of Medcne 340 (24), 1881-87. Hause, J. C., 2006. Offsettng behavor and the benefts of safety regulatons. Economc Inqury 44 (4), 689-98. Kahn, M. E., 1999. Dabetc rsk takng: The role of nformaton, educaton and medcaton. Journal of sk and Uncertanty 18 (2), 147-164. Lakdawalla, D., Sood, N., Goldman, D., 2006. HIV breakthroughs and rsky sexual behavour. Quarterly Journal of Economcs 121 (3), 1063-1102. Mller, G. E., Stagntt, M. N., 2005. Trends n statn use n the cvlan nonnsttutonalzed medcare populaton, 1997 and 2002. Statstcal Bref #43. July. Agency for Healthcare esearch and Qualty, ockvlle, MD. 63
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