There are probably several reasons why different studies have found different results. Some of it might be due to cultural differences or the fact that OCD looks different at different ages. Many of the studies were done in different countries and looked at different age groups (children, teenagers, or adults). Culture might be an important factor that researchers haven't studied enough when it comes to OCD. Also, even though OCD is considered a long-term condition that usually starts early in life, it looks very different in children compared to adults. More research is needed to understand how culture and different life stages affect when OCD starts and how it changes over time.