Voors en tegens van castratie/sterilisatie
Geplaatst: 08 dec 2008 11:33
Op een ander forum vond ik dit stuk:
"1) Onderzoek in Engeland: gecastreerde teven leven gemiddeld langer dan intacte teven, maar als je alleen kijkt naar honden die een natuurlijke dood zijn gestorven, dan blijkt dat intacte teven gemiddeld langer leven.
(2) Onderzoek onder 2002 honden in VS: gemiddeld leven gecastreerde honden langer dan intacte honden, maar het gevonden verschil is statistisch niet significant (en kan dus op toeval berusten).
(3) Onderzoek naar tumoren hart- en vaatstelsel bij honden: gecastreerde teven hebben een meer dan 4 keer groter risico dergelijke tumoren te ontwikkelen dan intacte teven; het risico van hemangiosarcoma is zelfs meer dan 5 x zo groot. Conclusie van het onderzoek: castratie verhoogt de kans op tumoren in hart- en vaatstelsel.
(4) Onderzoek onder 217 honden met miltkanker: gecastreerde teven lopen 2,2 keer zoveel risico op miltkanker (hemangiosarcoma/hematoma) als intacte teven.
(5) Onderzoek osteosarcoma: risico voor gecastreerde honden is twee keer zo groot als dat voor intacte honden.
(6) Onderzoek naar factoren die het ontstaan van melkklierkanker bij honden bevorderen: meer kans bij oudere teven, intacte teven of teven die na de leeftijd van 2,5 gecastreerd zijn; meer kans bij teven die al jong te dik zijn en bij teven die geen uitgebalanceerd voer krijgen.
(7) Idem, voeding in jeugd beïnvloedt kan op later ontwikkelen mammaetumoren.
(8) Onderzoek naar tumoren in blaas/urinewegen bij honden: gecastreerde honden lopen meer risico.
(9) Tulsa Kankerregistratie honden/katten: van ruim 63000 honden had 1% tumoren (goed- en kwaadaardig). De meest-voorkomende kwaadaardige kanker bij honden was melkklierkanker. [Maar “meest-voorkomend” onder 1% is nog steeds minder dan 1% - kortom, waar hebben we het over? Er gaan veel meer honden dood in het verkeer, aan andere kankervormen, aan epilepsie en noem maar op.]
(10) Hypothyroidie (te trage schildklier): castratie bleek de grootste risicofactor: gecastreerde honden lopen meer kans op schildklierafwijkingen dan intacte honden.
(11) Idem, bij gecastreerde teven was het verschil significant t.o.v. intacte teven.
(12) Onderzoek naar (dodelijke) acute pancreatitis: het risico van acute alvleesklierontsteking is hoger onder gecastreerde reuen en teven dan onder intacte teven.
(13) Idem (vergeleken met intacte reuen).
(14) Onderzoek naar incontinentie: gecastreerde teven lopen significant meer risico om incontinent te worden vanwege weefselveranderingen in de urinewegen oiv hormonen.
(15) Idem: onder gecastreerde teven komt 8 x zoveel incontinentie voor als onder intacte teven.
(16) Idem: 20% van de gecastreerde teven wordt incontinent.
(17) Gescheurde kruisbanden: gecastreerde reuen en teven lopen meer risico dan intacte honden.
(18) Idem, onderzoek onder ruim 10700 honden: meer risico voor gecastreerde honden.
(19) Obesitas: onder gecastreerde reuen en teven worden twee keer zoveel te dikke honden gevonden als onder intacte honden.
(20) Risicofactoren chronische keratitis (hoornvliesontsteking): onder honden van 4 jaar en jonger, lopen reuen en gecastreerde teven meer risico dan intacte teven (verschil statistisch significant).
Je zou voorzichtig kunnen concluderen dat dierenartsen pupeigenaars eerst bang maken met een verhaal over risico op mammaetumoren, ze dan de hemel beloven met het verlossende woord “vroege castratie”, maar daarbij verzwijgen dat (a) het risico om te beginnen al heel erg klein is, en (b) dat door castratie het risico van allerlei andere vormen van kanker en overige ellende gigantisch toeneemt.
Tenslotte: onder de 415 Drenten-teven waarvan we niet alleen de overlijdensdatum maar ook de overlijdensoorzaak weten, zijn er 4 waarbij melkklierkanker als oorzaak wordt opgegeven. Deze honden zijn gemiddeld 11,5 jaar geworden. De 914 Drenten waarvan we de overlijdensdatum weten en die door andere oorzaken dan melkklierkanker overleden, werden gemiddeld maar 9,2 jaar (alleen honden die geboren zijn voor 1-1-1994, en die inmiddels 13 konden zijn meegerekend). Dus zelfs het ontwikkelen van melkklierkanker betekent nog niet dat de honden eerder dood gaan dan andere Drenten – integendeel, zou je haast denken. Misschien is het gewoon een ouderdomsverschijnsel – uiteindelijk gaan we allemaal èrgens aan dood. "
(1) Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease.
Michell AR Centre for Small Animal Studies, Animal Health Trust, Newmarket, Suffolk. Vet Rec 1999 Nov 27;145(22):625-9
Neutered females lived longer than males or intact females, but among dogs dying of natural causes entire females lived slightly longer. In neutered males the importance of cancer as a cause of death was similar to heart disease.
(2) Variation in age at death of dogs of different sexes and breeds.
Bronson RT Am J Vet Res 1982 Nov;43(11):2057-9
A retrospective study of necropsy data for 2,002 dogs showed that the mean age at death of neutered dogs of both sexes exceeded that of intact dogs, but the differences were not significant.
(3) Cardiac tumors in dogs: 1982-1995.
Ware WA; Hopper DL Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011-1250, USA. J Vet Intern Med 1999 Mar-Apr;13(2):95-103
Tumors occurred with similar frequency in males and females, but the relative risk for spayed females was >4 times that for intact females. For HSA, spayed females had >5 times greater relative risk than did intact females. The risk for castrated males was slightly greater than that for intact males, which had 2.4 times the relative risk of intact females. Thus, neutering appeared to increase the risk of cardiac tumor in both sexes. Intact females were least likely to develop a cardiac tumor, whereas spayed females were most likely to develop a tumor.
(4) Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases (1985).
Prymak C; McKee LJ; Goldschmidt MH; Glickman LT Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania,Philadelphia 19104-6010. J Am Vet Med Assoc 1988 Sep 15;193(6):706-12
Compared with sexually intact females, only spayed females were at significantly (odds ratio [or], 2.2; 95% confidence interval [CI], 1.2 to 4.1) increased risk for developing SHS; sex predisposition was not found for dogs with SHA
(5) Host related risk factors for canine osteosarcoma.
Ru G; Terracini B; Glickman LT Department of Animal Pathology, University of Turin, Italy. cea@to.iZS.it Vet J 1998 Jul;156(1):31-9
A twofold excess risk was observed among neutered dogs.
(6) Factors influencing the incidence and prognosis of canine mammary tumours [In Process Citation]
Perez Alenza MD; Pena L; del Castillo N; Nieto AI Department of Animal Pathology II, Veterinary School, Complutense University, Madrid, Spain. J Small Anim Pract 2000 Jul;41(7):287-91
Increased age, intact status or ovariectomy after 2.5 years of age, as well as progestagen treatment, can all lead to an increased risk of mammary neoplasia in the bitch. In addition, obesity early in life, and a habitual diet based on home-made food (rich in beef and pork, and poor in chicken) as opposed to commercial food, are also associated with the occurrence of mammary tumours.
(7) Body conformation, diet, and risk of breast cancer in pet dogs: a case-control study.
Sonnenschein EG; Glickman LT; Goldschmidt MH; McKee LJ Department of Environmental Medicine, New York University Medical School, NY 10010. Am J Epidemiol 1991 Apr 1;133(7):694-703
The risk of breast cancer was significantly reduced in dogs spayed at or before 2.5 years of age. Neither a high-fat diet nor obesity 1 year before diagnosis increased the risk of breast cancer according to multiple logistic regression analysis. However, the risk of breast cancer among spayed dogs was significantly reduced in dogs that had been thin at 9-12 months of age (odds ratio (OR) = 0.04 (95% confidence interval (CI) 0.004-0.4) and OR = 0.04 (95% CI 0.004-0.5) for cases vs. cancer controls and cases vs. noncancer controls, respectively, after adjustment for age at spay). Among intact dogs, the risk associated with being thin at 9-12 months of age was reduced, but not significantly so (OR = 0.60 (95% CI 0.2-1.9) and OR = 0.51 (95% CI 0.2-1.4) for the two comparisons, respectively). Results of this study suggest that nutritional factors operating early in life may be of etiologic importance in canine breast cancer.
(8) Canine bladder and urethral tumors: a retrospective study of 115 cases (1980-1985).
Norris AM; Laing EJ; Valli VE; Withrow SJ; Macy DW; Ogilvie GK; Tomlinson J; McCaw D; Pidgeon G; Jacobs RM University of Guelph Ontario, Canada. J Vet Intern Med 1992 May-Jun;6(3):145-53
One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary
Cooperative Oncology Group. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers
(9) Frequency of canine and feline tumors in a defined population.
MacVean DW; Monlux AW; Anderson PS Jr; Silberg SL; Roszel JF Vet Pathol 1978 Nov;15(6):700-15
The Tulsa Registry of Canine and Feline Neoplasms was the second animal tumor registry in the United States concerned with a defined population in a delimited geographic area. Only tumors histologically confirmed by registry pathologists were included in frequency statistics based on the annual dog and cat population presented to veterinarians. During the first registry year, about 1% of the 63,504 dogs and 0.5% of the 11,909 cats had one or more primary tumors. While the incidence rate for malignant tumors in dogs was similar to that in cats, the incidence of benign tumors of dogs was over 10 times that of cats. The most common tumors were sebaceous adenoma in dogs and lymphosarcoma in cats. Mammary cancer was the most common malignant tumor in dogs. Mammary tumors of female dogs were significantly more frequent in Pointers, Poodles and Boston Terriers, in that order, than in other breeds. A greater incidence of mammary tumors among intact compared to spayed female dogs was seen for virtually every age group except in the Pointer breed.
(10) Hypothyroidism:
Hypothyroidism in dogs: 66 cases (1987-1992). Panciera DL Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706. J Am Vet Med Assoc 1994 Mar 1;204(5):761-7
Neutering was determined to be the most significant gender-associated risk factor for development of hypothyroidism. Neutered male and spayed female dogs had a higher relative risk of developing hypothyroidism than did sexually intact females. Sexually intact females had a lower relative risk.
(11) Epidemiologic features of canine hypothyroidism.
Milne KL; Hayes HM Jr Cornell Vet 1981 Jan;71(1):3-14
Spayed female dogs displayed a significantly higher risk when compared to intact females. Though not statistically significant, male castrated dogs had 30% more hypothyroidism compared to their intact counterparts
(12) Evaluation of risk factors for fatal acute pancreatitis in dogs.
Hess RS; Kass PH; Shofer FS; Van Winkle TJ; Washabau RJ : Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA. J Am Vet Med Assoc 1999 Jan
1;214(1):46-51
Males and neutered females appeared to have an increased risk of developing fatal acute pancreatitis, compared with sexually intact
females.
(13) Risk factors associated with acute pancreatitis in dogs: 101 cases (1985-1990).
Cook AK; Breitschwerdt EB; Levine JF; Bunch SE; Linn LO Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606. J Am Vet Med Assoc 1993 Sep 1;203(5):673-9
Spayed females and castrated male dogs had an increased risk, compared with that of sexually intact males.
(14) Urinary incontinence
Influence of ovariectomy on the canine striated external urethral sphincter (M. urethralis): a stereological analysis of slow and fast twitch fibres. Augsburger HR; Cruz-Orive LM Institute of Veterinary Anatomy, University of Zurich, Switzerland. Urol Res 1998;26(6):417-22.
The ovariectomized dogs exhibited a statistically significant lower type I and II fibre number and a concomitant slightly larger mean single profile area (diameter) of fibre type II compared with the control animals. The significantly reduced number and decreased total cross-sectional area of the fatigue-resistant type I fibres in ovariectomized dogs suggest a predominant weakening of the fibre type I portion of the M. urethralis as consequence of ovariectomy. The effect could be mediated by sex hormonal factors and may contribute to the development of postspaying urinary incontinence in female dogs
(15) Acquired urinary incontinence in bitches: its incidence and relationship to neutering practices.
Thrusfield MV; Holt PE; Muirhead RH Department of Veterinary Clinical Studies, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, Roslin, Midlothian. J Small Anim Pract 1998 Dec;39(12):559-66
A five-year cohort study was conducted on bitches chosen by a sample of 233 randomly selected practising veterinary surgeons in the UK, to estimate the incidence of acquired urinary incontinence (AUI) in neutered and entire animals, and to investigate possible risk factors associated with neutering practices. Information was collected using questionnaires, and data on 809 bitches, of which 22 developed AUI, were obtained. The estimated incidence rates in neutered and entire animals were 0.0174 and 0.0022 per animal-year, respectively (95 per cent confidence intervals: 0.0110, 0.0275 and 0.0009, 0.0058, respectively). The relative risk, neutered vs entire, was 7.8 (95 per cent confidence interval: 2.6, 31.5). The attributable proportion(exposed) and population attributable proportion were 87.1 per cent and 63.1 per cent (95 per cent confidence intervals: 61.9 per cent, 95.6 per cent, and 28.3 percent, 88.5 per cent, respectively). An increased risk, significant at the conventional 5 per cent level, was not demonstrated in animals neutered before, vs after, first heat (relative risk: 3.9, 95 per cent confidence interval: 0.8, 10.4), although the result was significant at the 10 per cent level. Removal of the cervix was not shown to be a risk factor in neutered dogs.
(16) [Urinary incontinence in castrated bitches. Part 1: Significance, clinical aspects and etiopathogenesis]
Harninkontinenz bei kastrierten Hundinnen. Teil 1: Bedeutung, Klinik und Atiopathogenese.
Arnold S Departement fur Fortpflanzungskunde, Veterinar-Medizinische Fakultat, Universitat Zurich. Schweiz Arch Tierheilkd 1997;139(6):271-6
Acquired urinary incontinence occurs in 20% of spayed females
(17) Orthopedics: Breed, sex, and body weight as risk factors for rupture of the cranial cruciate ligament in young dogs.
Duval JM; Budsberg SC; Flo GL; Sammarco JL Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA. J Am Vet Med Assoc 1999 Sep 15;215(6):811-4
Increased risk was detected for neutered males and neutered females, compared with sexually intact males and sexually intact females, respectively. Differences in prevalence of rupture of the CCL were not detected between all males and females, sexually intact males and sexually intact females, or neutered males and neutered females. Body weights of dogs with ruptured CCL were significantly greater than those of control dogs.
(18) Epidemiology of cranial cruciate ligament rupture in dogs.
Whitehair JG; Vasseur PB; Willits NH Veterinary Medical Teaching Hospital, Department of Surgery, School of Veterinary Medicine, University of California, Davis 95616. J Am Vet Med Assoc 1993 Oct
1;203(7):1016-9
Data from 10,769 dogs with rupture of the cranial cruciate ligament (CCL) Neutered dogs, whether male or female, had a higher prevalence of CCL rupture than did sexually intact dogs. The dog's age at the time of ovariohysterectomy was not associated with prevalence of CCL rupture.
(19) Study of obesity in dogs visiting veterinary practices in the United Kingdom.
Edney AT; Smith PM Vet Rec 1986 Apr 5;118(14):391-6
Neutered females were about twice as likely to be obese as entire females. The same trend was evident with neutered males.
(20) Risk factors for development of chronic superficial keratitis in dogs.
Chavkin MJ; Roberts SM; Salman MD; Severin GA; Scholten NJ Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523. J Am Vet Med Assoc 1994 May 15;204(10):1630-4
Among dogs < 4 years old, spayed females, sexually intact males, and castrated males were more likely to develop the condition (P < 0.05) than were sexually intact females.
Het is dus niet altijd zo zwart/wit als weleens gesteld wordt
"1) Onderzoek in Engeland: gecastreerde teven leven gemiddeld langer dan intacte teven, maar als je alleen kijkt naar honden die een natuurlijke dood zijn gestorven, dan blijkt dat intacte teven gemiddeld langer leven.
(2) Onderzoek onder 2002 honden in VS: gemiddeld leven gecastreerde honden langer dan intacte honden, maar het gevonden verschil is statistisch niet significant (en kan dus op toeval berusten).
(3) Onderzoek naar tumoren hart- en vaatstelsel bij honden: gecastreerde teven hebben een meer dan 4 keer groter risico dergelijke tumoren te ontwikkelen dan intacte teven; het risico van hemangiosarcoma is zelfs meer dan 5 x zo groot. Conclusie van het onderzoek: castratie verhoogt de kans op tumoren in hart- en vaatstelsel.
(4) Onderzoek onder 217 honden met miltkanker: gecastreerde teven lopen 2,2 keer zoveel risico op miltkanker (hemangiosarcoma/hematoma) als intacte teven.
(5) Onderzoek osteosarcoma: risico voor gecastreerde honden is twee keer zo groot als dat voor intacte honden.
(6) Onderzoek naar factoren die het ontstaan van melkklierkanker bij honden bevorderen: meer kans bij oudere teven, intacte teven of teven die na de leeftijd van 2,5 gecastreerd zijn; meer kans bij teven die al jong te dik zijn en bij teven die geen uitgebalanceerd voer krijgen.
(7) Idem, voeding in jeugd beïnvloedt kan op later ontwikkelen mammaetumoren.
(8) Onderzoek naar tumoren in blaas/urinewegen bij honden: gecastreerde honden lopen meer risico.
(9) Tulsa Kankerregistratie honden/katten: van ruim 63000 honden had 1% tumoren (goed- en kwaadaardig). De meest-voorkomende kwaadaardige kanker bij honden was melkklierkanker. [Maar “meest-voorkomend” onder 1% is nog steeds minder dan 1% - kortom, waar hebben we het over? Er gaan veel meer honden dood in het verkeer, aan andere kankervormen, aan epilepsie en noem maar op.]
(10) Hypothyroidie (te trage schildklier): castratie bleek de grootste risicofactor: gecastreerde honden lopen meer kans op schildklierafwijkingen dan intacte honden.
(11) Idem, bij gecastreerde teven was het verschil significant t.o.v. intacte teven.
(12) Onderzoek naar (dodelijke) acute pancreatitis: het risico van acute alvleesklierontsteking is hoger onder gecastreerde reuen en teven dan onder intacte teven.
(13) Idem (vergeleken met intacte reuen).
(14) Onderzoek naar incontinentie: gecastreerde teven lopen significant meer risico om incontinent te worden vanwege weefselveranderingen in de urinewegen oiv hormonen.
(15) Idem: onder gecastreerde teven komt 8 x zoveel incontinentie voor als onder intacte teven.
(16) Idem: 20% van de gecastreerde teven wordt incontinent.
(17) Gescheurde kruisbanden: gecastreerde reuen en teven lopen meer risico dan intacte honden.
(18) Idem, onderzoek onder ruim 10700 honden: meer risico voor gecastreerde honden.
(19) Obesitas: onder gecastreerde reuen en teven worden twee keer zoveel te dikke honden gevonden als onder intacte honden.
(20) Risicofactoren chronische keratitis (hoornvliesontsteking): onder honden van 4 jaar en jonger, lopen reuen en gecastreerde teven meer risico dan intacte teven (verschil statistisch significant).
Je zou voorzichtig kunnen concluderen dat dierenartsen pupeigenaars eerst bang maken met een verhaal over risico op mammaetumoren, ze dan de hemel beloven met het verlossende woord “vroege castratie”, maar daarbij verzwijgen dat (a) het risico om te beginnen al heel erg klein is, en (b) dat door castratie het risico van allerlei andere vormen van kanker en overige ellende gigantisch toeneemt.
Tenslotte: onder de 415 Drenten-teven waarvan we niet alleen de overlijdensdatum maar ook de overlijdensoorzaak weten, zijn er 4 waarbij melkklierkanker als oorzaak wordt opgegeven. Deze honden zijn gemiddeld 11,5 jaar geworden. De 914 Drenten waarvan we de overlijdensdatum weten en die door andere oorzaken dan melkklierkanker overleden, werden gemiddeld maar 9,2 jaar (alleen honden die geboren zijn voor 1-1-1994, en die inmiddels 13 konden zijn meegerekend). Dus zelfs het ontwikkelen van melkklierkanker betekent nog niet dat de honden eerder dood gaan dan andere Drenten – integendeel, zou je haast denken. Misschien is het gewoon een ouderdomsverschijnsel – uiteindelijk gaan we allemaal èrgens aan dood. "
(1) Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease.
Michell AR Centre for Small Animal Studies, Animal Health Trust, Newmarket, Suffolk. Vet Rec 1999 Nov 27;145(22):625-9
Neutered females lived longer than males or intact females, but among dogs dying of natural causes entire females lived slightly longer. In neutered males the importance of cancer as a cause of death was similar to heart disease.
(2) Variation in age at death of dogs of different sexes and breeds.
Bronson RT Am J Vet Res 1982 Nov;43(11):2057-9
A retrospective study of necropsy data for 2,002 dogs showed that the mean age at death of neutered dogs of both sexes exceeded that of intact dogs, but the differences were not significant.
(3) Cardiac tumors in dogs: 1982-1995.
Ware WA; Hopper DL Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011-1250, USA. J Vet Intern Med 1999 Mar-Apr;13(2):95-103
Tumors occurred with similar frequency in males and females, but the relative risk for spayed females was >4 times that for intact females. For HSA, spayed females had >5 times greater relative risk than did intact females. The risk for castrated males was slightly greater than that for intact males, which had 2.4 times the relative risk of intact females. Thus, neutering appeared to increase the risk of cardiac tumor in both sexes. Intact females were least likely to develop a cardiac tumor, whereas spayed females were most likely to develop a tumor.
(4) Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases (1985).
Prymak C; McKee LJ; Goldschmidt MH; Glickman LT Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania,Philadelphia 19104-6010. J Am Vet Med Assoc 1988 Sep 15;193(6):706-12
Compared with sexually intact females, only spayed females were at significantly (odds ratio [or], 2.2; 95% confidence interval [CI], 1.2 to 4.1) increased risk for developing SHS; sex predisposition was not found for dogs with SHA
(5) Host related risk factors for canine osteosarcoma.
Ru G; Terracini B; Glickman LT Department of Animal Pathology, University of Turin, Italy. cea@to.iZS.it Vet J 1998 Jul;156(1):31-9
A twofold excess risk was observed among neutered dogs.
(6) Factors influencing the incidence and prognosis of canine mammary tumours [In Process Citation]
Perez Alenza MD; Pena L; del Castillo N; Nieto AI Department of Animal Pathology II, Veterinary School, Complutense University, Madrid, Spain. J Small Anim Pract 2000 Jul;41(7):287-91
Increased age, intact status or ovariectomy after 2.5 years of age, as well as progestagen treatment, can all lead to an increased risk of mammary neoplasia in the bitch. In addition, obesity early in life, and a habitual diet based on home-made food (rich in beef and pork, and poor in chicken) as opposed to commercial food, are also associated with the occurrence of mammary tumours.
(7) Body conformation, diet, and risk of breast cancer in pet dogs: a case-control study.
Sonnenschein EG; Glickman LT; Goldschmidt MH; McKee LJ Department of Environmental Medicine, New York University Medical School, NY 10010. Am J Epidemiol 1991 Apr 1;133(7):694-703
The risk of breast cancer was significantly reduced in dogs spayed at or before 2.5 years of age. Neither a high-fat diet nor obesity 1 year before diagnosis increased the risk of breast cancer according to multiple logistic regression analysis. However, the risk of breast cancer among spayed dogs was significantly reduced in dogs that had been thin at 9-12 months of age (odds ratio (OR) = 0.04 (95% confidence interval (CI) 0.004-0.4) and OR = 0.04 (95% CI 0.004-0.5) for cases vs. cancer controls and cases vs. noncancer controls, respectively, after adjustment for age at spay). Among intact dogs, the risk associated with being thin at 9-12 months of age was reduced, but not significantly so (OR = 0.60 (95% CI 0.2-1.9) and OR = 0.51 (95% CI 0.2-1.4) for the two comparisons, respectively). Results of this study suggest that nutritional factors operating early in life may be of etiologic importance in canine breast cancer.
(8) Canine bladder and urethral tumors: a retrospective study of 115 cases (1980-1985).
Norris AM; Laing EJ; Valli VE; Withrow SJ; Macy DW; Ogilvie GK; Tomlinson J; McCaw D; Pidgeon G; Jacobs RM University of Guelph Ontario, Canada. J Vet Intern Med 1992 May-Jun;6(3):145-53
One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary
Cooperative Oncology Group. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers
(9) Frequency of canine and feline tumors in a defined population.
MacVean DW; Monlux AW; Anderson PS Jr; Silberg SL; Roszel JF Vet Pathol 1978 Nov;15(6):700-15
The Tulsa Registry of Canine and Feline Neoplasms was the second animal tumor registry in the United States concerned with a defined population in a delimited geographic area. Only tumors histologically confirmed by registry pathologists were included in frequency statistics based on the annual dog and cat population presented to veterinarians. During the first registry year, about 1% of the 63,504 dogs and 0.5% of the 11,909 cats had one or more primary tumors. While the incidence rate for malignant tumors in dogs was similar to that in cats, the incidence of benign tumors of dogs was over 10 times that of cats. The most common tumors were sebaceous adenoma in dogs and lymphosarcoma in cats. Mammary cancer was the most common malignant tumor in dogs. Mammary tumors of female dogs were significantly more frequent in Pointers, Poodles and Boston Terriers, in that order, than in other breeds. A greater incidence of mammary tumors among intact compared to spayed female dogs was seen for virtually every age group except in the Pointer breed.
(10) Hypothyroidism:
Hypothyroidism in dogs: 66 cases (1987-1992). Panciera DL Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706. J Am Vet Med Assoc 1994 Mar 1;204(5):761-7
Neutering was determined to be the most significant gender-associated risk factor for development of hypothyroidism. Neutered male and spayed female dogs had a higher relative risk of developing hypothyroidism than did sexually intact females. Sexually intact females had a lower relative risk.
(11) Epidemiologic features of canine hypothyroidism.
Milne KL; Hayes HM Jr Cornell Vet 1981 Jan;71(1):3-14
Spayed female dogs displayed a significantly higher risk when compared to intact females. Though not statistically significant, male castrated dogs had 30% more hypothyroidism compared to their intact counterparts
(12) Evaluation of risk factors for fatal acute pancreatitis in dogs.
Hess RS; Kass PH; Shofer FS; Van Winkle TJ; Washabau RJ : Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA. J Am Vet Med Assoc 1999 Jan
1;214(1):46-51
Males and neutered females appeared to have an increased risk of developing fatal acute pancreatitis, compared with sexually intact
females.
(13) Risk factors associated with acute pancreatitis in dogs: 101 cases (1985-1990).
Cook AK; Breitschwerdt EB; Levine JF; Bunch SE; Linn LO Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606. J Am Vet Med Assoc 1993 Sep 1;203(5):673-9
Spayed females and castrated male dogs had an increased risk, compared with that of sexually intact males.
(14) Urinary incontinence
Influence of ovariectomy on the canine striated external urethral sphincter (M. urethralis): a stereological analysis of slow and fast twitch fibres. Augsburger HR; Cruz-Orive LM Institute of Veterinary Anatomy, University of Zurich, Switzerland. Urol Res 1998;26(6):417-22.
The ovariectomized dogs exhibited a statistically significant lower type I and II fibre number and a concomitant slightly larger mean single profile area (diameter) of fibre type II compared with the control animals. The significantly reduced number and decreased total cross-sectional area of the fatigue-resistant type I fibres in ovariectomized dogs suggest a predominant weakening of the fibre type I portion of the M. urethralis as consequence of ovariectomy. The effect could be mediated by sex hormonal factors and may contribute to the development of postspaying urinary incontinence in female dogs
(15) Acquired urinary incontinence in bitches: its incidence and relationship to neutering practices.
Thrusfield MV; Holt PE; Muirhead RH Department of Veterinary Clinical Studies, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, Roslin, Midlothian. J Small Anim Pract 1998 Dec;39(12):559-66
A five-year cohort study was conducted on bitches chosen by a sample of 233 randomly selected practising veterinary surgeons in the UK, to estimate the incidence of acquired urinary incontinence (AUI) in neutered and entire animals, and to investigate possible risk factors associated with neutering practices. Information was collected using questionnaires, and data on 809 bitches, of which 22 developed AUI, were obtained. The estimated incidence rates in neutered and entire animals were 0.0174 and 0.0022 per animal-year, respectively (95 per cent confidence intervals: 0.0110, 0.0275 and 0.0009, 0.0058, respectively). The relative risk, neutered vs entire, was 7.8 (95 per cent confidence interval: 2.6, 31.5). The attributable proportion(exposed) and population attributable proportion were 87.1 per cent and 63.1 per cent (95 per cent confidence intervals: 61.9 per cent, 95.6 per cent, and 28.3 percent, 88.5 per cent, respectively). An increased risk, significant at the conventional 5 per cent level, was not demonstrated in animals neutered before, vs after, first heat (relative risk: 3.9, 95 per cent confidence interval: 0.8, 10.4), although the result was significant at the 10 per cent level. Removal of the cervix was not shown to be a risk factor in neutered dogs.
(16) [Urinary incontinence in castrated bitches. Part 1: Significance, clinical aspects and etiopathogenesis]
Harninkontinenz bei kastrierten Hundinnen. Teil 1: Bedeutung, Klinik und Atiopathogenese.
Arnold S Departement fur Fortpflanzungskunde, Veterinar-Medizinische Fakultat, Universitat Zurich. Schweiz Arch Tierheilkd 1997;139(6):271-6
Acquired urinary incontinence occurs in 20% of spayed females
(17) Orthopedics: Breed, sex, and body weight as risk factors for rupture of the cranial cruciate ligament in young dogs.
Duval JM; Budsberg SC; Flo GL; Sammarco JL Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA. J Am Vet Med Assoc 1999 Sep 15;215(6):811-4
Increased risk was detected for neutered males and neutered females, compared with sexually intact males and sexually intact females, respectively. Differences in prevalence of rupture of the CCL were not detected between all males and females, sexually intact males and sexually intact females, or neutered males and neutered females. Body weights of dogs with ruptured CCL were significantly greater than those of control dogs.
(18) Epidemiology of cranial cruciate ligament rupture in dogs.
Whitehair JG; Vasseur PB; Willits NH Veterinary Medical Teaching Hospital, Department of Surgery, School of Veterinary Medicine, University of California, Davis 95616. J Am Vet Med Assoc 1993 Oct
1;203(7):1016-9
Data from 10,769 dogs with rupture of the cranial cruciate ligament (CCL) Neutered dogs, whether male or female, had a higher prevalence of CCL rupture than did sexually intact dogs. The dog's age at the time of ovariohysterectomy was not associated with prevalence of CCL rupture.
(19) Study of obesity in dogs visiting veterinary practices in the United Kingdom.
Edney AT; Smith PM Vet Rec 1986 Apr 5;118(14):391-6
Neutered females were about twice as likely to be obese as entire females. The same trend was evident with neutered males.
(20) Risk factors for development of chronic superficial keratitis in dogs.
Chavkin MJ; Roberts SM; Salman MD; Severin GA; Scholten NJ Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523. J Am Vet Med Assoc 1994 May 15;204(10):1630-4
Among dogs < 4 years old, spayed females, sexually intact males, and castrated males were more likely to develop the condition (P < 0.05) than were sexually intact females.
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