Appendicitis: Trends in incidence, age, sex, and seasonal variations in South-Western Nigeria

BACKGROUND: Appendicitis is a common clinical condition worldwide. Differences in incidences, sex, age, and seasonal variations have been reported widely, with paucity of information from Nigeria. AIM: To assess the trends in incidence and pattern of variation with age, sex, and seasons of the year. MATERIALS AND METHODS: A review of the records of all patients with confirmed appendicitis treated in both the LAUTECH Teaching Hospital (LTH) and the Abake Medical Center (AMC), both situated in Osogbo, Nigeria, between January 2003 and December 2008, was done. LTH was a 320-bed University Hospital (with 100 surgical beds), while AMC was a 20-bed surgical center. The age, sex, and month of admission of all the histologically proven cases of appendicitis were retrieved and treated. Analysis was done using simple percentages, Student t or Chi-square tests, where applicable. RESULTS: A total of 299 out of 321 cases of appendicitis recorded during the observed period were confirmed histologically from both hospitals (69.56% from LTH). Fifty-two percent were males. It made up 0.94, 1.43, and 1.86% of the total hospital admissions in 2004, 2006, and 2008, respectively. There has been an increasing incidence in both sexes almost in a similar pattern. The overall mean age was 25.79 years (M 25.94 and F 25.43 years) with 6% below the age of ten and 1.3% above 60 years. The highest incidence in males and females occurred in the second and third decades, respectively. Incidences were higher during the rainy season (April to September) 68%, P < 0.05), with peaks from June to August, when 39.5% of all cases presented. CONCLUSION: The increasing incidence of appendicitis in both sexes in this region may be due to the change to a Western lifestyle. The age distribution has a similar pattern in both sexes and 87% are 40 years or less, although the incidence is marginally higher in males. Higher prevalence of infections and allergens from pollens in the rainy season could contribute to a higher incidence of appendicitis.