Revista de Saúde Pública
I SSN 0034- 8910 versão im pressa
Rev Saúde Pública 2003; 37(5)
PSA and anthropometric measurements among Amaz on Indians:
an evaluation of the Parkatejê community
Hom ero Oliveira de Arruda, JPB Vieira Filho, V Ort iz and M Srougi
Escola Paulist a de Medicina da Universidade Federal de São Paulo. São Paulo, SP, Brasil
ABSTRACT
Objective
PSA ( p r ost at e- specific ant igen) scr eening for ear ly det ect ion of pr ost at e cancer in a nat iv e com m unit y is of great epidem iological im por t ance. The pr esent st udy w as conduct ed w it h t he obj ect iv e of ver ifying t he occur r ence of pr ost at e cancer am ong m em ber s of an Am azon com m unit y, as w ell as it s possible relat ionship t o accult urat ion and overw eight ( body m ass index) .
Methodology
Lifest y le and ant hropom et ric inform at ion was collect ed from a group of 22 m en, presum edly over age 50, m em bers of an isolat ed com m unit y of 363 Am azonian I ndians – self - denom inat ed Parkat ej ê and Ky k at êj ê – from Pará st at e, in Nort hern Brazil. I n addit ion t o physic al and hem at ological exam s, t ot al and free PSA dosages were perform ed.
Tot al PSA serum levels ranged from 0.35 t o 25.8 ng/ m l. Three subj ect s had PSA levels great er t han 4.0 ng/ m l, and anot her t wo had levels bet ween 2.5 and 4.o ng/ m l. Prost at ic bio psies perform ed on t w o subj ect s indicat ed t he pr esence of pr ost at e adenocar cinom a in one of t hem and of int r aepit helial neoplasia on t he ot her . Ov er w eight ( BMI =25 Kg/ m ² ) and waist - t o- hip rat io =0,9 w er e obser ved in 68.1% and 72% of subj ect s, r espect iv ely .
Conclusions
Changes in nut r it ional habit s caused by cont act w it h civ ilizat ion, such as t he subst it ut ion of m or e calor ic foods for t he t r adit ional gam e and veget able fiber ar e incr easing t he pr evalence of over w eight am ong t he com m unit y. I n view of t he asso ciat ion bet w een pr ost at e cancer incidence, high- fat diet , and less phy sical act iv it y , it can be assum ed t hat fur t her cases of pr ost at e neoplasia w ill occur in t he fut ure, since several com m unit y m em bers already have high PSA serum levels.
Keywords
Pr ost at ic neoplasm s, diagnosis. Prost at ic neoplasm s, epidem iology. Prost at e- specific ant igen, diagnost ic use. Body m ass index. I ndians, Sout h Am erican. Ant hropom et ry. Risk fact ors. Obesit y. Accult ur at ion. Food habit s. Pr ev alence.
I N TRODUCTION
The discov er y , in t he last decades, of abnor m al am ount s of pr ost at e- specific ant igen ( PSA) in t he blood ser um of pat ient s w it h pr ost at e adenocar cinom as caused a r evolut ion in t he appr oach t o t his disease. PSA is a prot ease of t he kallikrein fam ily, produced alm ost exclusively by t he epit helium of t he prost at e gland, in order t o solubilize sperm aft er ej aculat ion. I t s level frequent ly increases during benign hyperplasias and prost at it is, and high serum levels can be obser v ed in pat ient s w it h pr ost at e car cinom a. The im por t ance of PSA dosage for clinical pr act ice has caused it t o becom e t he m ost im por t ant r esour ce for t he ear ly diagnosis and follow- up of pr ost at e cancer pat ient s. I t s m agnit ude is such t hat pr ost at e canc er is current ly t he m ost diagnosed int ernal cancer am ong m en, PSA dosages ident ify ing ov er 80% of new localized cases of t his disease.2
I m plicat ions concerning t he differences observed in serum PSA levels am ong African- Am ericans, whit es, and Hispanics in a num ber of et hnic m inor it ies hav e been t he subj ect of debat e for y ear s.5 Such differ ences m ay be connect ed t o t he biological differ ences am ong differ ent et hnicit ies, and m ay account for v ar iat ions in pr ost at e cancer incidence. Could t hey be genet ic det er minant s, w it h biological char act er ist ics pr oper of each individual, or ar e t hey her edit ar y t r ait s, w hich suffer environm ent al m odificat ion according t o lifest yle and nut rit ional habit s?
Differ ences in pr ost at e cancer fr equency am ong Alask an- bor n Caucasians and Nat ive- Am ericans have been w ell docum ent ed.1 , 3 , 1 3 The pr esent st udy is aim ed at ver ifying t he t r end t ow ar ds t he appear ance of pr ost at e cancer and it s possible r elat ion t o lifest yle and envir onm ent al fact or s am ong Am azon I ndians. Wit h t his in m ind, ant hropom et rical charact erist ics and serum PSA levels am ong t his group w er e analy zed.
Methods
Tw en t y - two me dical records of Parkat ej ê and Kikat êj ê I ndians, from t he healt hcare service for I ndians m aint ained by t he Vale do Rio Doce m ining com pany w er e analy zed r et r ospect iv ely . These nat iv es belong t o a Tim bir a t ribe derived from t he Jê language group. They live in t he sout heast er n r egion of t he st at e of Par á, in West er n Am azon, in a r eser v at ion delim it ed as a r esult of t he const r uct ion of t he Car aj ás – I t aquí railroad, begun in 1980. The group com prises 363 I ndians, whose nut rit ional cust om s and t r adit ions had been preserved unt il t hen; t hese included gam e, fish, w ild fruit , and root s. Since t hat t im e, t he gr oup has had int er m it t ent and pr ogr essiv e cont act w it h w hit e civ ilizat ion. Am ong t hese 363 nat ives, an ant hropologist was able t o ident ify 22 m en presum edly aged 50 years or older. All of t hem allow ed blood t o be dr aw n for analy sis, aft er an isolat ed case of acut e ur inar y r et ent ion due t o a benign pr ost at e hy per plasia w as ident ified and sur gically t r eat ed at t he Univ er sit y Hospit al. I n addit ion t o t he blood t est , a sim ple physical exam inat ion was carried out , and ant hropom et rical m easurem ent s were regist ered in order t o obt ain body m ass index ( BMI ) , ( norm al < 25 Kg/ m ² ) , and waist - t o- hip rat io ( WHR) , ( norm al < 0.9) m easures. Biochem ical dosages were carried out , including t ot al blood PSA, t hrough im m unefluorescence. When t his level w as above 2.5 ng/ m l, free/ t ot al PSA rat io w as m easured, ( norm al: 4.0 ng/ m l and 0.72 ng/ m l) . Prost at ic biopsies, under anest hesia, were indicat ed in case of fr ee/ t ot al r at ios below 15% , and subj ect t o subj ect consent . Digit al r ect al ex am inat ion could only be perform ed during biopsy.
RESULT S
PSA result s are present ed in Table 1. Tot al PSA values varied bet ween 0.35 and 25.8 ng/ m l. Three subj ect s had PSA lev els gr eat er t han 4.0 ng/ m l ( 5.33, 8.64, and 25.8) , and anot her t w o bet w een 2.5 and 4.0 ng/ m l ( 2.6 and 3.2) . I n four of t hese t he free/ t ot al PSA rat io w as below 15% . Only t w o subj ect s consent ed t o digit al exam inat ion and biopsy. These revealed an adenocarcinom a nodule ( Gleason score 3+ 2) in one subj ect and a high- grade int raepit helial neoplasm in t he ot her. The pat ient wit h cancer is st ill under LHRH- analog t r eat m ent .
Ta ble 1 - Age, t ot al and free PSA values, and FPSA/ TPSA rat io am ong nat ives aged 50 years or older.
Cont r ol
Ag e
Tot al PSA
Free PSA
FPSA/ T P SA (% ) 35 57 0.59
36 68 1. 3
37 76 5.33 0.44 8.26 39 79 25.8 1.15 4.46* 40 56 0.85
43 59 1.86
44 58 8.64 0.36 4 . 1 7 * * 46 66 1
57 62 2.42 62 57 1.77
63 56 2. 6 0.37 14.23
66 70 1.06
83 56 3. 2 0.73 22.81
87 72 0.36 91 70 2.03 92 68 0.35
* Biopsy w it h pr ost at e adenocar cinom a.
* * Biopsy w it h high- level int r aepit helialneoplasia.
PSA – Pr ost at e- specific ant igen
TPSA –Tot al PSA
Ant hropom et ric m easurem ent s, PSA r esult s, and t he cor r elat ions obt ained bet w een v alues for all 22 subj ect s ar e list ed in Table 2. Despit e t he suggest iv e associat ions obser v ed w hen com par ing st udy populat ion v alues, t her e w er e no st at ist ically significant associat ions bet w een Weight , ( r= 0.162843) , BMI (r= - 0.02416) and WHR ( r= 0.132533) .
Ta b le 2 – Age, w eight , PSA values, body m ass index, w aist - t o- hip rat io, p25, p75, and m edian value am ong nat ives aged 50 years or older.
Con t r ol Ag e Weig ht Tot al PSA
BMI WHR
35 56 67.4 0.59 25.6 6
0. 8913 86 36 61 59.3 1.30 21.2
0
0.8779 44 37 78 71.5 5.33 24.7
4
0.9864 86 39 76 77.8 25.8 26.3
0
0.9616 20 40 58 64.1 0.85 26.0
1
0.8984 13 43 56 64.9 1.86 22.7
2
0.8977 78 44 57 72.1 8.64 26.1
6
0.9488 82 46 59 63.0 1.00 23.7
1
0.9100 06 47 64 65.5 0.31 26.5
7
0. 9368 42 48 61 74.4 1.86 25.7
4
0.9288 66 50 78 60.0 0.41 24.5
0
51 55 88.7 0.66 28.9 6
0.9180 41 53 58 82.9 0.74 26.6
1
0.9497 32 57 67 80.0 2.42 28.0
0
1.0005 14 58 78 76.8 1.51 28.5
5
1.0005 15 62 60 77.3 1.77 28.0
5
0.9979 25 63 58 80.4 2. 6 27.4
8
1.0030 61 66 66 74.3 1.06 28.4
7
0.9888 55 83 61 59.3 3. 2 22.8
6
0.8811 71 87 68 70.1 0.36 25.4
4
0.9442 06 91 73 69.4 2.03 23.1
9
0.8936 84 92 72 78.0 0.35 31.2
0
1.0051 30 p2 5 0 .6 8 2 4 .5
6
0 .9 0 1 3 1 1 p7 5 2 .3 2 2 5 2 7 .8
7
0 .9 8 8 2 6 3 Media
n
1.405 26.0 85
0.9405 24
BMI – Body m ass index
WHR – Waist - t o- hip ratio
D ISCUSSION
Th e f ir st can cer- relat ed st udies am ong Nort h- Am erican indigenous groups dem onst rat ed t hat st om ach, int est ine, r ect um , pr ost at e, and liver cancer incidences in t his gr oup w er e sim ilar t o t hose found am o ng w hit e Am ericans. Lung, breast , and bladder cancer, how ever, w ere com parat ively rare am ong Nat ive- Am er icans. Hist ological t y pes w er e t he usual, w it h t he ex cept ion of bladder cancer , for w hich fiv e in ev er y eight cases w er e squam ous cell car cinom as, and only t hree w ere t ransit ional epit helium carcinom as.3
Hist orically, cont act w it h civilizat ion has result ed in progressive social and behavioral changes am ong indigenous peoples, discouraging t hem from seeking m ore nat ural foods and significant ly alt ering t heir nut r it ional habit s. These phenom ena w er e follow ed by t he appear ance of diseases t hat ar e com m on am ong t he gener al populat ion, such as t y pe I I diabet es, chr onic degener at iv e diseases, and cancer .1 4 This new diet w as ident ified as t he lik ely culpr it for t he incr ease in pr ost at e cancer incidence, obser v ed bet w e en t he 1968- 72 and 1978- 82 periods am ong Nat ive - Am ericans from Nort h Carolina.9 Despit e it s possible causes being som ew hat cont r ov er sial, t he associat ion bet w een t his t y pe of cancer and fat -r ich diet s had al-r eady been post ulat ed at t hat t im e.4,8
I n 1995, Whit t em ore et al,1 5 in a st udy of t he r elat ionship of pr ost at e cancer t o diet , phy sical act iv it y , and body m ass in African- Am ericans, whit es, and Asians living in t he US and Canada, found a significant r isk associat ion bet w een t his neoplasia and t ot al fat ingest ion in all et hnic groups. This associat ion w as at t r ibut ed solely t o t he ex cessiv e calor ies or iginat ed fr om sat ur at ed fat s, and not t o t hose r elat ed t o pr ot ein or car bohy dr at es. At t he t im e, r isk w as not associat ed w it h BMI or phy sical act iv it y pat t er n s. The aut hor s suggest ed t hat ot her fact or s, in addit ion t o sat ur at ed fat ingest ion, could account for t he differ ent r isk lev els obser v ed for t he differ ent et hnic gr oups. Recent st udies w it h cer t ain specific gr oups, how ev er , hav e det ect ed an im por t ant associat ion bet w een pr ost at e cancer r isk and BMI . Hsing et al1 0 found an alm ost t hreefold risk ( OR 2.71wit h 95% CI ) am ong Chinese in t he highest WHR quart ile.
Gener ically , colon and pr ost at e cancer r isk s can be posit iv ely cor r elat ed t o a fat - r ich diet ; t hese t um ors have a 50% higher chance of occurrence when com pared t o t he risk found am ong individuals w it h norm al diet s. Likew ise, fruit , veget able, and legum e ingest ion is associat ed w it h lesser colon and lung cancer incidence.1
I n addit ion t o t he nut rit ional aspect , a lifest yle including r egular physical act ivit y pr obably has a relevant role in t his equilibrium , regulat ing individual necessit ies.1 , 7 Thus t he possibilit y t o st udy a
pr im it ive com m unit y allow s us t o explor e t he r ole played by genet ic fact or s and t heir expression in t he unfolding of a disease, isolat ed for m any influence of t he habit s of civ ilizat ion. The st udy of t he Parkat ej ê and Kikat êj ê indigenous com m unit ies – w hich w ere subm it t ed only recent ly t he nut rit ional habit s of w hit e civ ilizat ion – m ay reinforce such assum pt ions, since BMI and WHR analysis in t his com m unit y revealed t hat 68.1% and 72.7% of nat ives over age 50 had result s com pat ible wit h over w eight . I n t he sam e line of t hought , it can be assum ed t hat t he nat ives’ t r adit ional diet unt il t w o decades ago w as r elat ed t o a r eal and unk now n occur r ence of pr ost at e cancer am ong t hat populat ion. I n t he pr esent sur v ey , occur r ence w as one confir m ed and one suspect case of spor adic cancer , t he lat t er suffering from a high- degree int raepit helial neopla sm .
Resear cher s and ant hr opologist s, w hen st udy ing diet indicat ions in ancient civ ilizat ions and t he ut ensils of ancient t im es, believ ed t hat , in addit ion t o foods of v eget able or igin, such as cer eals, fr uit , and legum es, t he wild m eat of gam e was also low in f at .7
Biologically, one of t he explanat ions for t his phenom enon m ay be t he associat ion wit h an increased r esist ance t o insulin, obser v ed in connect ion w it h phy sical act iv it y r educt ions due t o t he decr ease in hunt ing and food collect ion act iv it ies. I n addit ion, r ecent obser v at ions indicat e t hat pr ost at e and br east cancer ar e associat ed t o incr eases in I GF - 1( insulin growt h fact or- 1) levels, which m ay influence t he pr olifer at ion of pr ost at e- can cer cells.6 I t is possible t hat ex er cise, t hr ough t he reduct ion of insulin resist ance or I GF - 1 levels, m ay play a role, m odulat ing som ehow t he appearance of prost at e cancer.
The pr esence of incr eased PSA lev els in fiv e out of 22 nat iv es ( 23% ) is sim ilar t o t he pr ev alence found am ong t he general whit e Am erican populat ion,2 w hich suggest s t hat t he Pak at ej ê and Kik at êj ê com m unit y is appr oaching t he w hit e populat ion in t er m s of pr ost at e cancer incidence. I n ot her w or ds, pr ost at e cancer incidence does r eally incr ease w hen indigenous populat ions incor por at e t he habit s of so- called “ civilized” populat ions.
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15. Whit t em ore AS, Kolonel LN, Wu AH, John EM, Gallagher RP, Howe GR et al. Prost at e cancer in r elat ion t o diet , phy sical act iv it y , and body size in black s, w hit es, and Asians in t he Unit ed St at es and Canada. J Nat l Cancer I nst 1995; 87: 652 - 61.
Address to correspondence
Hom ero Oliveira de Arruda 04024 - 002, São Paulo, SP, Brazil E- m ail: arrudas@dglnet .com .br
Receiv ed on 30/ 6/ 2002. Reviewed on 28/ 4/ 2003. Approved on 3/ 6/ 2003.
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