In addition there were 68 sub-topics with fewer than five reviews available, such as lung cancer, testicular cancer, food service inspection, fetal alcohol syndrome, sexual assault, and social justice. The full list of subtopics with fewer than five reviews is included in Table  5 . Most of the sub-topics with fewer than five reviews were within the registered users and visitors' topic areas of interest. Topic areas which were of interest to both registered user and visitors only had a small proportion of sub-topics with less than five reviews available (child health, chronic diseases, mental health, nutrition, and social determinants of health). Whereas the communicable disease/infection topic area, which ranked tenth among registered users, had the largest proportion of sub-topics with fewer than five reviews (n = 16). While environmental health and food safety and inspection were not preferred topic areas for registered users and visitors, a large portion of the subtopics in these two categories had fewer than 5 reviews. Although there is currently a lack of review literature in these areas, these topics have been mentioned by public health professionals as relevant to public-health practice.