In the beginning of the 20th century, tonsillectomy became more common in the United Kingdom and the United States and by the 1930s was very common in both countries. For example, a study conducted in 1934 found that 61% of 1,000 New York schoolchildren had been tonsillectomized; doctors recommended surgery for all but 65 of the remaining children. Complications were often simply accepted. The medical community considered enlarged tonsils a disease, attributing their enlargement to infection rather than a physiologic response. Because of the theory of focal infection, many surgeons believed that not only enlarged tonsils, but all tonsils should be removed. In the 1940s tonsillectomy became controversial as several studies linked it to bulbar poliomyelitis. From the 1940s to 1970s, further studies found an association between tonsillectomy and bulbar poliomyelitis with recommendations not to do the operation during outbreaks. Controversy surrounding tonsillectomy increased further in the United Kingdom in the 1960s because of the financial costs associated with the number of surgeries being performed and because of unexplainable variations in tonsillectomy rates between geographic regions and between social classes. In the media, tonsillectomy was criticised for being "fashionable" or a "status symbol". There was also an increasing concern regarding the psychological and physical suffering of young children as a result of surgery. Furthermore, opponents of surgery argued that the tonsils should be retained whenever possible because of their role in the immune system and that the benefits of surgery were marginal. In the 1970s, tonsillectomy rates in the United Kingdom started to decline after several studies concluded that tonsillectomy was not as effective for sore throats and many other indications as previously thought.