vertisements for products whose efficacy and safety have been established by the Department of National Health and Welfare is misleading. Its adornment with scientific references only adds to the obfuscation, and we find it particularly galling to be cited in an argument supporting dieting behaviour. David S. Goldbloom, MD Ron Davis, PhD Allan S. Kaplan, MD Sidney H. Kennedy, MD Carla Rice, AB The Programme for Eating Disorders The Toronto Hospital Toronto, Ont.
Reference 1. Ratnasuriya RH, Eisler I, Szmukler GJ et al: Anorexia nervosa: outcome and prognostic factors after 20 years. Br J Psychiatry 1991; 158: 495-502
[The manufacturer responds.] At any given moment almost one in three Canadian men and one in two Canadian women are attempting to lose weight. Researchers and clinicians agree on the serious negative health implications of excess body weight and yo-yo dieting, yet thousands of Canadians continue to maintain body weights above those suggested for optimum health. With the help of a team of clinical dietitians and physicians we have developed a range of appetizing meal replacements that are nutritionally balanced according to Canada's nutrient intake recommendations. Each of our products contains 50% to 60% carbohydrates, less than 30% fat, 15% protein and the 22 essential nutrients recommended for good health. Slim-Fast products also contain 2 g of dietary fibre per serving, and Ultra Slim-Fast products contain 4 g per serving. Both types of product are low in sodium and cholesterol and adaptable to many therapeutic indications. We recommend consumers 200
CAN MED ASSOC J 1991; 145 (3)
replace one or two meals per day with a Slim-Fast product. A 7-day 1200-kcal (5040 kJ) diet sheet developed by clinical dietitians is included with each product. Each low-fat, wholesome meal in the diet plan accounts for approximately 400 kcal (1680 kJ). Healthy snacks of fresh fruits and vegetables make up another 200 kcal (840 Id) daily. In this way we help consumers to make wise nutritional choices, and we hope to retrain their eating habits step by step in a manner that is easy and motivational. In addition, our product insert sheet encourages consumers to visit their physician before beginning to diet and to set realistic weight goals. It discusses weight maintenance and exercise as part of a healthy lifestyle. Jerry Abraham, BS Pharm, MS President Stella Pharmaceutical Company Limited Don Mills, Ont.
Interchangeability of oral contraceptive products T n he special article in CMAJ (1991; 144: 1223-1224), by the Expert Advisory Committee on Bioavailability, Health Protection Branch (HPB), Department of National Health and Welfare, makes statements that sound to the average reader as if blood level analysis of oral contraceptives is the accepted norm for generic substitution. This, however, is not the case. The committee's workshop held on June 4, 1990, consisted almost exclusively of analytic chemists and pharmacochemists, who did not examine in detail the question of clinically proven interchange-
ability. Clinical effectiveness is clearly the most crucial measure of oral contraceptive performance since even minor variations of the es-
tablished standard may cause a considerable increase in the number of unwanted pregnancies. For this reason the Pharmaceutical Manufacturers Association of Canada formally requested the HPB to hold another workshop, this time for clinicians to discuss the subject and express their concerns on behalf of practising physicians. The HPB agreed to organize such a workshop. Only after the forum of practitioners reaches a consensus on the role of clinical tests in establishing therapeutic equivalence can the interchangeability of oral contraceptive products be considered for final ruling. Miklos Nadasdi, MD, PhD Medical director Wyeth Ltd. North York, Ont.
Serious childhood injuries caused by air guns S urely such articles as the one by Drs. Amir Shanon and William Feldman (Can Med Assoc J 1991; 144: 723-725) that show tunnel vision and personal bias have no place in a scientific publication. Since historic times wellmeaning but misguided people have sought to make life safer by attempting to ban activities not conforming to their own lifestyle. Shannon and Feldman have placed themselves among the misguided. Their demand for a ban on air guns and their suggestions on how to make such guns safer can only be described as naive. After a lifetime in medical practice I can still marvel at the variety of activities that pass for sport and our inconsistent attitude toward the injuries sustained during those activities. An eye injury caused by a golf ball is acceptable, but one caused by a pellet gun is an occasion for pub( LE jer AOJT 1991
lic outcry. A death on the ski slopes is a regrettable misfortune, but one that occurs in an all-terrain vehicle results in a call for a ban. As physicians it is our duty to speak out on dangerous sports, to educate the public on the need for controls or supervision and to treat resulting injuries. It is never our place to seek to ban any sport because it is not our own. When physicians use their authority to speak on subjects in which they lack expertise they do us all a disservice. Donald R. Maclnnis, MD Shubenacadie Medical Centre Shubenacadie, NS
The article by Drs. Shanon and Feldman is important in reminding us of how much injury can be suffered by the misuse of air guns. However, little is known of the actual risk of handling air guns in general: the number of accidents per total number of air guns or per hours of use. Thus the authors' conclusion that "their sale needs to be banned or at least carefully regulated" needs further comment. To ban air guns would be an unfortunate action for the following reasons. Air guns provide pleasure to users of all ages, not only children. They are often a way for children to imitate an adult - often a parent who gave them the air gun as a gift - who shoots powdered weapons. So the air gun is a means of practising target shooting in preparation for hunting at a later age. As well as for hunting, air guns are used for informal shooting at homemade targets, and target shooting can lead to national and international competition and even the Olympics. Good competitors have often begun their training in childhood. Research should focus on the circumstances of air weapon accidents in order to prevent them. Injuries to the eyes are often the AUGUST 1, 1991
result of ricochets, which can be completely avoided if an adequate backstop is provided and protective goggles are worn. To restrict "air gun use to supervised target ranges" would be unnecessary if an adequate backstop and parental supervision were provided. In recent years the two largest air gun companies in North America have explained in their instruction booklets the safety rules regarding backstop choice, goggles and safe weapon handling; they have even gone to the extent of casting the main instructions on the airgun barrels. New airgun designs include a greater trigger pull (the effort needed to pull the trigger and fire) and safety buttons providing a tactile and visual clue that the airgun is loaded. With all these precautions it is clear that a lack of proper adult supervision is likely responsible for most accidents. Future studies will need to determine whether children with injuries were using recently built, safer North American air guns, were supervised, were using a backstop and were wearing goggles. The most powerful air guns (with a velocity above 152 m/s) are already sufficiently regulated in Canada. Sales of other air guns (with a velocity under 152 m/s) should not be banned; rather their sale (but not their use) should be restricted to adults. Children using air guns should be supervised closely by an adult. Pierre-Etenne Senal MD 1001 Potrero Ave. San Francisco, Calif.
We refer them to our report in the ophthalmic literature a few years ago describing 16 children with BB gun injuries.' As in the children described by Shanon and Feldman the visual injuries were universally debilitating, and 42% were blinded in the affected eye. Regarding the authors' recommendation for prospective studies on various aspects of air gun injuries we are hopeful that the current Children's Hospital Injury Reporting Program and the Toy-induced Eye Injury Study endorsed by the Canadian Ophthalmological Society and conducted by the Department of Ophthalmology at the Izaak Walton Killam Children's Hospital will help in gathering useful information. G. Robert LaRoche, MD Lynn McIntyre, MD Departments of Ophthalmology, Pediatrics and Epidemiology Izaak Walton Killam Children's Hospital Halifax, NS
Reference 1. LaRoche GR, McIntyre L, Schertzer RM: Epidemiology of severe eye inju-
ries in childhood. Ophthalmology 1988; 95: 1603-1607
[Dr. Feldman responds.] In Funk and Wagnalls Standard Desk Dictionary' science is defined as "knowledge of facts, phenomena, laws and proximate causes, gained and verified by exact observation, organized experiment, and ordered thinking." I feel certain that Dr. MacInnis would not take issue with the facts, phenomena and proximate causes that were the basis of our paper. The facts are that a large number of children were seriously injured - four of them having lost an eye - and that the causes were air guns. It is likely that MacInnis is describing our solutions as "showing tunnel vision and personal bias." If he has better solutions
We read with interest Drs. Shanon and Feldman's report of the air gun injuries to 43 children admitted to the Children's Hospital of Eastern Ontario. We fully agree with the authors' recommendation to ban the sale of air guns to Canadian children and their call for better education of than those we offered in our artiparents. CAN MED ASSOC J 1991; 145 (3)
201
Reference 1. Ratnasuriya RH, Eisler I, Szmukler GJ et al: Anorexia nervosa: outcome and prognostic factors after 20 years. Br J Psychiatry 1991; 158: 495-502
[The manufacturer responds.] At any given moment almost one in three Canadian men and one in two Canadian women are attempting to lose weight. Researchers and clinicians agree on the serious negative health implications of excess body weight and yo-yo dieting, yet thousands of Canadians continue to maintain body weights above those suggested for optimum health. With the help of a team of clinical dietitians and physicians we have developed a range of appetizing meal replacements that are nutritionally balanced according to Canada's nutrient intake recommendations. Each of our products contains 50% to 60% carbohydrates, less than 30% fat, 15% protein and the 22 essential nutrients recommended for good health. Slim-Fast products also contain 2 g of dietary fibre per serving, and Ultra Slim-Fast products contain 4 g per serving. Both types of product are low in sodium and cholesterol and adaptable to many therapeutic indications. We recommend consumers 200
CAN MED ASSOC J 1991; 145 (3)
replace one or two meals per day with a Slim-Fast product. A 7-day 1200-kcal (5040 kJ) diet sheet developed by clinical dietitians is included with each product. Each low-fat, wholesome meal in the diet plan accounts for approximately 400 kcal (1680 kJ). Healthy snacks of fresh fruits and vegetables make up another 200 kcal (840 Id) daily. In this way we help consumers to make wise nutritional choices, and we hope to retrain their eating habits step by step in a manner that is easy and motivational. In addition, our product insert sheet encourages consumers to visit their physician before beginning to diet and to set realistic weight goals. It discusses weight maintenance and exercise as part of a healthy lifestyle. Jerry Abraham, BS Pharm, MS President Stella Pharmaceutical Company Limited Don Mills, Ont.
Interchangeability of oral contraceptive products T n he special article in CMAJ (1991; 144: 1223-1224), by the Expert Advisory Committee on Bioavailability, Health Protection Branch (HPB), Department of National Health and Welfare, makes statements that sound to the average reader as if blood level analysis of oral contraceptives is the accepted norm for generic substitution. This, however, is not the case. The committee's workshop held on June 4, 1990, consisted almost exclusively of analytic chemists and pharmacochemists, who did not examine in detail the question of clinically proven interchange-
ability. Clinical effectiveness is clearly the most crucial measure of oral contraceptive performance since even minor variations of the es-
tablished standard may cause a considerable increase in the number of unwanted pregnancies. For this reason the Pharmaceutical Manufacturers Association of Canada formally requested the HPB to hold another workshop, this time for clinicians to discuss the subject and express their concerns on behalf of practising physicians. The HPB agreed to organize such a workshop. Only after the forum of practitioners reaches a consensus on the role of clinical tests in establishing therapeutic equivalence can the interchangeability of oral contraceptive products be considered for final ruling. Miklos Nadasdi, MD, PhD Medical director Wyeth Ltd. North York, Ont.
Serious childhood injuries caused by air guns S urely such articles as the one by Drs. Amir Shanon and William Feldman (Can Med Assoc J 1991; 144: 723-725) that show tunnel vision and personal bias have no place in a scientific publication. Since historic times wellmeaning but misguided people have sought to make life safer by attempting to ban activities not conforming to their own lifestyle. Shannon and Feldman have placed themselves among the misguided. Their demand for a ban on air guns and their suggestions on how to make such guns safer can only be described as naive. After a lifetime in medical practice I can still marvel at the variety of activities that pass for sport and our inconsistent attitude toward the injuries sustained during those activities. An eye injury caused by a golf ball is acceptable, but one caused by a pellet gun is an occasion for pub( LE jer AOJT 1991
lic outcry. A death on the ski slopes is a regrettable misfortune, but one that occurs in an all-terrain vehicle results in a call for a ban. As physicians it is our duty to speak out on dangerous sports, to educate the public on the need for controls or supervision and to treat resulting injuries. It is never our place to seek to ban any sport because it is not our own. When physicians use their authority to speak on subjects in which they lack expertise they do us all a disservice. Donald R. Maclnnis, MD Shubenacadie Medical Centre Shubenacadie, NS
The article by Drs. Shanon and Feldman is important in reminding us of how much injury can be suffered by the misuse of air guns. However, little is known of the actual risk of handling air guns in general: the number of accidents per total number of air guns or per hours of use. Thus the authors' conclusion that "their sale needs to be banned or at least carefully regulated" needs further comment. To ban air guns would be an unfortunate action for the following reasons. Air guns provide pleasure to users of all ages, not only children. They are often a way for children to imitate an adult - often a parent who gave them the air gun as a gift - who shoots powdered weapons. So the air gun is a means of practising target shooting in preparation for hunting at a later age. As well as for hunting, air guns are used for informal shooting at homemade targets, and target shooting can lead to national and international competition and even the Olympics. Good competitors have often begun their training in childhood. Research should focus on the circumstances of air weapon accidents in order to prevent them. Injuries to the eyes are often the AUGUST 1, 1991
result of ricochets, which can be completely avoided if an adequate backstop is provided and protective goggles are worn. To restrict "air gun use to supervised target ranges" would be unnecessary if an adequate backstop and parental supervision were provided. In recent years the two largest air gun companies in North America have explained in their instruction booklets the safety rules regarding backstop choice, goggles and safe weapon handling; they have even gone to the extent of casting the main instructions on the airgun barrels. New airgun designs include a greater trigger pull (the effort needed to pull the trigger and fire) and safety buttons providing a tactile and visual clue that the airgun is loaded. With all these precautions it is clear that a lack of proper adult supervision is likely responsible for most accidents. Future studies will need to determine whether children with injuries were using recently built, safer North American air guns, were supervised, were using a backstop and were wearing goggles. The most powerful air guns (with a velocity above 152 m/s) are already sufficiently regulated in Canada. Sales of other air guns (with a velocity under 152 m/s) should not be banned; rather their sale (but not their use) should be restricted to adults. Children using air guns should be supervised closely by an adult. Pierre-Etenne Senal MD 1001 Potrero Ave. San Francisco, Calif.
We refer them to our report in the ophthalmic literature a few years ago describing 16 children with BB gun injuries.' As in the children described by Shanon and Feldman the visual injuries were universally debilitating, and 42% were blinded in the affected eye. Regarding the authors' recommendation for prospective studies on various aspects of air gun injuries we are hopeful that the current Children's Hospital Injury Reporting Program and the Toy-induced Eye Injury Study endorsed by the Canadian Ophthalmological Society and conducted by the Department of Ophthalmology at the Izaak Walton Killam Children's Hospital will help in gathering useful information. G. Robert LaRoche, MD Lynn McIntyre, MD Departments of Ophthalmology, Pediatrics and Epidemiology Izaak Walton Killam Children's Hospital Halifax, NS
Reference 1. LaRoche GR, McIntyre L, Schertzer RM: Epidemiology of severe eye inju-
ries in childhood. Ophthalmology 1988; 95: 1603-1607
[Dr. Feldman responds.] In Funk and Wagnalls Standard Desk Dictionary' science is defined as "knowledge of facts, phenomena, laws and proximate causes, gained and verified by exact observation, organized experiment, and ordered thinking." I feel certain that Dr. MacInnis would not take issue with the facts, phenomena and proximate causes that were the basis of our paper. The facts are that a large number of children were seriously injured - four of them having lost an eye - and that the causes were air guns. It is likely that MacInnis is describing our solutions as "showing tunnel vision and personal bias." If he has better solutions
We read with interest Drs. Shanon and Feldman's report of the air gun injuries to 43 children admitted to the Children's Hospital of Eastern Ontario. We fully agree with the authors' recommendation to ban the sale of air guns to Canadian children and their call for better education of than those we offered in our artiparents. CAN MED ASSOC J 1991; 145 (3)
201
