High rates of diabetes have been observed among Arab populations in the Middle East (1). We aimed to determine the prevalence of previously diagnosed and undiagnosed diabetes in Greater Beirut, which includes Administrative Beirut and its suburban part of Mount Lebanon. This part of Lebanon is home to 53.6% of the population and represents a mixture of urban and rural areas with different socioeconomic classes.
A multistage random probability sample was devised using the population distribution suggested by the Lebanese Central Administration of Statistics. Despite a minor and insignificant deviation, the quota that best represents Greater Beirut was achieved.
A research team conducted a door-to-door survey. A total of 3,000 exclusively Lebanese citizens ≥40 years of age (mean 55.5 [95% CI 55.2–55.9]) were interviewed and asked about prior medical diagnosis of diabetes.
On the next morning, venous blood was collected from subjects who did not report a previous diagnosis of diabetes and accepted enrollment in the study. Blood could not be obtained from people who did not fast for 12 h overnight or could not be available at the scheduled appointment. Venous whole blood was transported within 2 h to our laboratory (affiliated with the Faculty of Medical Sciences of the Lebanese University). Plasma glucose concentrations were measured by an automated glucose oxidase method using Roche Diagnostics Reagents.
The 1997 American Diabetes Association criteria for the diagnosis of diabetes and impaired fasting glucose were used.
All statistical analysis was done using SPSS. The differences between the scalded/ratio variables under consideration were analyzed by z test (Gaussian test). P < 0.05 was considered statistically significant.
Of the 3,000 individuals recruited, 339 were found to have previously diagnosed diabetes, representing a prevalence of 11.3% (95% CI 10.2–12.4). Only two subjects met epidemiological criteria for type 1 diabetes. This prevalence increased with age but this increase was not significant for subjects ≥70 years of age. When we took into consideration the whole population studied, the prevalence of previously diagnosed diabetes was significantly higher in men (P = 0.001), although the difference was not statistically significant for subjects ≥50 years of age.
In the group that did not report a previous diagnosis of diabetes, fasting plasma glucose was measured in 551 individuals; the remaining subjects were not tested. The sampled and unsampled groups were not statistically different concerning age and sex.
We found 28 individuals with undiagnosed diabetes and 14 with impaired fasting glucose, which constitutes a prevalence of 5.1% (95% CI 3.2–6.9) and 2.5% (95% CI 1.2–3.9), respectively. The combined prevalence of previously diagnosed and newly diagnosed diabetes was 15.8% (95% CI 14.5–17.1); 17.6% (95% CI 15.8–19.4) in men and 13.4% (95% CI 11.5–15.3) in women (P = 0.002). In the U.S., 6.3% of the population has diabetes: 4.5% diagnosed and 1.8% undiagnosed (2). The ratio of known to unknown diabetes obtained in our study was similar to the one recognized in the U.S.
These results suggest that the prevalence of diabetes in Greater Beirut is high. Larger samples covering different areas in Lebanon are needed to estimate the national prevalence of diabetes.
