The term diabetes mellitus describes a heterogenous group of disorders that share in common an elevated blood glucose level. The word diabetes, coined from the Greek word for 'syphon' by Aretaeus of Cappadocia in the first century A.D., refers to the characteristic symptoms of intense thirst, profuse urination, and rapid wasting leading to coma and death. Mellitus was added when the sweetness of the urine indicating its high sugar content was noted by Thomas Willis (1621-1675), thus distinguishing the disorder from the insipid, sugar-free variety.

The earliest evidence pointing to an interest in diabetes on the part of Maltese medical practitioners dates to the late seventeenth century. The National Malta Library holds a number of medical books belonging to contemporary practitioners which discuss various aspects of the disease. The first mention of the disease affecting a Maltese individual dates to an eighteenth century case report of a nun who suffered from diabetes and who in a space of ninety-four days voided 3,594 chamber-pots of urine. This case was described by Dr. Giuseppe Demarco (1712-1789). Dr. Demarco also in 1764 wrote a dissertation De carbunculo seu anthrace on one of the complications of long-standing diabetes, namely carbuncles, in which he discussed the development, diagnosis and treatment of this condition.

Increasing recognition of the importance of this disease in the nineteenth century is reflected by the delivery of lectures on diabetes in 1826 by the Professor of Medicine to medical students. From the 1830s onwards, British, Italian and French ideas moulded the methods of management of the disease on the part of medical practitioners. By 1872, conditions such as carbuncles, loss of vision and gangrene of the lower limbs were recognised as complications of the disease. During this century, diet was the sheet anchor of treatment. Insulin therapy was introduced in Malta in 1922-23, a year after its discovery abroad. The initial interest in the disease was limited more to its management and the treatment of its complications rather than the pattern of disease in the population. However an increased predisposition of the Maltese to carbuncles was noted by a number of practitioners during the nineteenth century.

Diabetes mellitus remains an important cause of mortality in Malta. Maltese mortality statistics by cause of death are available since the turn of the twentieth century. The annual mortality trends in the Maltese Islands since 1896 shows two characteristic peaks in 1942 and 1970s (Figure 1).

There is previous to these peaks mild upward trends with the annual figures exhibiting wide irregular divergences from the trend. The peak of 1942, coincides with the post-Second World War period. Insufficiency of hypoglycaemic drug stores may in part explain the high mortality of this period. It may however have resulted from the nutritional insults suffered by the population during the war years. A second peak in mortality rates from diabetes mellitus can be noted in the early 1970s, this following a gradual rise initiated in the late 1950s. This peak was maintained, after a drop in the late 1970s, to the early 1980s. The factors accounting for this rise, included (1) an increased awareness of the disease; (2) increased efforts at detection; and (3) a general increase in life expectancy. The changes in mortality rates are also influenced by the age structure of the population, which was markedly influenced during the 1960s by emigration patterns. The fall in specific mortality rate in the late 1970s can be attributable to better management of the disease and its complications, and/or to changes in mortality registration practice. The specific mortality rate from diabetes mellitus in the general population in the last decade averaged 38.5 per 100,000 population, this being higher in the female population averaging 46.8 per 100,000 females.

Awareness of the role of diabetes as a public health problem was manifested by the Chief Government Officer in 1952, who commented that "excessive calorie consumption through many years may also be the cause of the growing incidence of diabetes mellitus which is again on the increase since the war". At this time diabetic retinopathy was found to account for 15.9 per cent of blindness. The first Diabetes Clinic was opened at St. Luke's Teaching Hospital in 1963, while Community Diabetes Clinics came into operation in 1968 and expanded in 1974. The Maltese Diabetes Association was founded in 1981. The earliest epidemiological study was carried out by Prof. J.V. Zammit-Maempel in 1964-65 who reported that 17.2% of the population were diabetic. The prevailing form of diabetes was shown to be the maturity onset or non-insulin dependant type in the peak ages of 50-54 years; the juvenile form being uncommon. The disease was commoner in females having a male:female ratio of 1:1.6. Sixty per cent of diabetics were obese and 51 per cent had arterial complications.

The next epidemiological study using modern criteria was conducted in the early 1980s. The first phase of the study confirmed that the major form of diabetes in Malta was Type 2 or non-insulin dependant diabetes with an overall prevalence of 7.7 per cent while the minor form of the disorder - impaired glucose tolerance -occurred in a further 5.6 per cent of thee population. The rates were higher in the elderly and in women. The prevalence of previously diagnosed diabetics amounted to 0.5%. Type 1 or insulin dependant diabetes has a prevalence of 81.2 per 100,000 population aged 0-14 years. The prevalence in subjects below 20 years was 117 per 100,000 population of that age.

The first significant mention of pregnancy complicating diabetes was made by J.M. Duncan in 1882 in a review describing 22 diabetic pregnancies. He also reports the occurrence of diabetes "only during pregnancy, being absent other times". Subsequent early twentieth century reviews highlighted the high maternal and fetal mortality associated with DM and the low reproductive success of diabetic women. The high prevalence of Type II or non-insulin dependant diabetes in the Maltese female population suggests a concomitant increase of abnormal glucose metabolism in the Maltese pregnant population. Diabetes mellitus complicating pregnancy was first mentioned in 1937 when glucosuria was reported to be one of the most frequent complication of pregnancy accounting for 3.2 per cent of all hospital deliveries. Retrospective studies have suggested that the incidence of diabetes mellitus in the hospital pregnant population in the 1970s-1990s ranged from 0.64 - 2.2 per cent, the rate depending on the degree of screening. Of these, 0.25 per cent were patients with pre-existing diabetes. Screening studies have suggested that a larger proportion of women develop gestational impaired glucose metabolism of varying severity (Table 1).

Table 1: Prevalence rates of AGT in Maltese females
AGE GROUP.........Total AGT......IGT......new DM......old DM
15-44 years
# non-pregnant.......2.2%........1.7%.......-...........0.5%
# pregnant..........15.1%.......14.0%......0.8%.........0.3%
45-54 years.........18.2%........7.1%......2.7%.........8.4%
55-64 years.........26.2%........7.7%......1.8%........16.7%
>65 years...........44.5%.......15.7%.....19.6%.........9.2%

In conformity to studies in other populations, Maltese patients with gestational or pre-existing diabetes mellitus have been shown on retrospective study to be generally elderly. The prevalence of diabetes mellitus and IGT disorders during pregnancy were estimated in the 1980s at 1.1% in women aged 20-29 years, 1.7% in those aged 30-34 years, 2.1% in those aged 35-39 years and 5.2% in those aged more than 40 years. These women were also generally obese and have had a number of previous pregnancies of which a significant number had been lost in the form of miscarrages or child deaths.

Before the discovery of insulin by Frederick Banting and Charles H. Best in 1921, those women with IDDM who survived to the reproductive age and were able to become pregnant had less than a 50 per cent chance of having a living child or of surviving the pregnancy. The advent of insulin brought about a dramatic change in the overall outlook for diabetics and their reproductive potential. The maternal mortality fell from about 45 per cent to just over 2 per cent shortly after the introduction of insulin. There is no information available about the contribution of diabetes mellitus towards maternal mortality in Malta. The first recorded maternal death in a diabetic in Malta was in 1937, whereas the last recorded diabetic maternal death occurred in 1974.

The perinatal mortality, unlike maternal mortality, did not fall dramatically but rather decreased slowly with time. With improvements in the understanding of the pathophysiology of diabetic pregnancies, and the advent of effective antenatal monitoring and management, the perinatal outcome has now significantly improved. Diabetes mellitus during pregnancy remains an important cause of pregnancy loss in Malta. Thus, during the years 1979-1982, the specific perinatal mortality rate for identified diabetic mothers delivering in Malta was 121.8 per 1000 total births. This high rate was significantly reduced following a increased awareness campaign about gestational diabetes in the subsequent years 1983-1986, when the perinatal death rate in diabetics fell to 24.9 per 1000 total births. Furthermore diabetes results in a disturbance of the environment of the unborn child that may seriously affect its development and physiology, not only by causing its death but also by damaging its organs predisposing it to develop diabetes later on in life. Infants of diabetic mothers are generally born of a heavier birth weight than those born to other women. A large number of infants of high birth weight are born in the Maltese Islands, so that 11.8 per cent of the newborn population weighs 4 kg or over, the high rate reflecting the commoner prevalence of the disorder. In addition infants of Maltese diabetic mothers are twice as likely to have congenital malformations. The management of the pregnant woman with diabetes still continues to present a challenge, though the problems are now different. Reduction of perinatal loss is no longer a sufficient end point. Instead, success must be judged by a reduction in the frequency and consequences of large birth weight to that found in non-diabetic pregnancies.

Diabetes mellitus remains an important disorder in the Maltese population, contributing significantly towards population morbidity and mortality. Health plan strategies must consider the various facets of management, ranging from screening methods for early detection through facilities for adequate treatment of the disease and its complications. Educational programmes regarding healthy nutrition must be aimed at all levels of the population particularly the young and pregnant population.