Jamaica is an island in the Caribbean approximately 140 km south of Cuba. Maximum dimensions are 235 km long and 84 km wide, with a land mass of 10,911 km2 and an estimated population of 2.9 million in 2018. The people are predominantly of West African origin, with smaller groups from India, China, the Mediterranean, and northern Europe, especially the United Kingdom. This diversity results in a population where 10% have the sickle cell trait, 3.5% have the HbC trait, and 0.9% have the β thalassemia trait. Although Jamaica is in many ways a developing society, it has excellent public health and medical facilities and is malaria free. Furthermore, some sophistication results from its closeness geographically to the United States and culturally to the United Kingdom, which also means that these countries are home to a large Jamaican diaspora. Within Jamaica, despite a shift of the population toward urban centers, nearly half the people reside in rural areas where they maintain stable households. This population structure is invaluable for long-term follow-up of patients and, hence, ideal for studies of the natural history of disease generally and has provided a unique “island laboratory” for studies of sickle cell disease.
The Sickle Cell Clinic in Jamaica
The Sickle Cell Clinic at the University Hospital of the West Indies was started by Dr. Paul Milner in 1965 and gradually increased in size until it served 5500 patients with sickle cell disease by 1999. Supported by the British Medical Research Council from 1972, the staff grew from 2 to 28, and with further support from a locally based charity, the Sickle Cell Trust, the facilities steadily improved, with the opening of a dedicated Sickle Cell Clinic in 1988. In addition, due to a bequest from the local cable and wireless facilities, an Education Centre for Sickle Cell Disease opened in 1994. Clinics were conducted 5-and-a-half days per week, and an electronic patient management system allowed real-time collection of clinical, hematologic, and other data, which were immediately available for patient management and research.
In 1966, there was a striking discrepancy between the mild clinical features of many patients in the recently formed Sickle Cell Clinics and the almost uniformly severe disease described in the contemporary textbooks, suggesting that there may have been a symptomatic bias in the medical experience of the disease. This hypothesis was tested by seeking to trace 50 patients with SS disease then aged >30 years who had not been seen by the clinics at the University Hospital for >10 years. The natural assumption was that these patients had died. Funded by the Wellcome Trust, a mobile clinical unit (Figure 32-1) traced patients to their homes, where 5 were found to have emigrated, 5 had died, 17 were untraceable, and 23 were located and well. When questioned, most stated that their symptoms ...