<p>The Prevalence of Isolated Neutropenia at High Altitude in Southern Saudi Arabia: Does Altitude Affect Leucocyte Count?</p>

Abstract

Introduction: Isolated neutropenia is a common problem in hematology practice. Benign ethnic neutropenia (BEN) is the common form of neutropenia worldwide and it affects mainly African and Middle Eastern ethnicities. Most cases of isolated mild and moderate neutropenia are benign and associated with no clinical significance. The aim of this study was to estimate the prevalence of isolated neutropenia at high-altitude southern Saudi Arabia. Methods: A large dataset of complete blood counts (CBCs) was analyzed for walk-in patients of both genders, of age ranges from 12 to 60 years doing blood tests at a commercial lab for high altitude − 2,270 meters above sea level-(HA) group, and from sea level SL group. Abnormal biochemical or CBC results were excluded before analysis. Results: For HA group, 3123 CBCs were analyzed and for SL group 18,427 CBCs were analyzed. The prevalence of mild neutropenia, defined as absolute neutrophil count (ANC) in the range of 1.0−.5× 10 9 /L, was 12.4% (n=399) versus 5.6% (n=1025), while moderate neutropenia, defined as ANC of 0.5-1 × 10 9 /L, was present 6% (n=191) versus 1.45% (n=269) in the high altitude and sea level groups, respectively. Severe neutropenia, defined as neutrophil count less than 0.5-1 × 10 9 /L, was rare in both groups. Conclusion: Isolated neutropenia is common in Saudis living at high altitude. While benign ethnic neutropenia (BEN) is thought to be the major contributing factor to this high prevalence, other factors including environmental factors and altitude are possible contributing factors along with underlying ethnic neutropenia.

Isolated Neutropenia/Benign Ethnic Neutropenia: A Common Clinical and Laboratory Finding in Southern and Western Saudi Arabia

“…The current study validates our previous findings in which the prevalence of neutropenia was found to be 18%. 14 The findings of this study are consistent with those of Gari et al 12 who also reported a high prevalence (20%) of neutropenia in Jeddah. Several other studies have shown a variable frequency of neutropenia among different populations.…”

“…We previously noticed a higher prevalence of isolated neutropenia at a high altitude in comparison with sea level. 14 In this study, the prevalence of isolated neutropenia in Taif city (1898 m above sea level) was not different from that in the coastal Jeddah city in the current study. Furthermore, in this study, we did not find any association between altitude levels and hematocrit (as a surrogate for decreased plasma volumes).…”

“… 8 , 11–13 We previously showed that a higher prevalence of isolated neutropenia was observed in two cities (Jeddah and Abha) in Saudi Arabia. 14 Saudi Arabia, representing the larger part of the Arabian peninsula, is inhabited by mainly Arab tribes of Semitic origin. In this study, we aimed to confirm our previous findings through a large sample size from seven different cities at different altitudes (Jeddah, Taif, Al Baha, Abha, Khamis Mushait, Najran, and Gizan) in Southern and Southwestern Saudi Arabia.…”

Isolated Neutropenia/Benign Ethnic Neutropenia: A Common Clinical and Laboratory Finding in Southern and Southwestern Saudi Arabia

“…We previously noticed a higher prevalence of isolated neutropenia at a high altitude in comparison with sea level [12]. In this study, the prevalence of isolated neutropenia in Taif city (1,898 m above sea level) was not different from that in the coastal Jeddah city in the current study.…”

“…BEN is most common in Africans, Afro-Americans, Ethiopian Jews, and Yemenite Jews [6,[9][10][11]. We previously showed that a higher prevalence of isolated neutropenia was observed in two cities (Jeddah and Abha) in Saudi Arabia [12]. We aimed to confirm our previous findings through a large sample size from seven different cities (Jeddah, Taif, Al Baha, Abha, Khamis Mushait, Najran, and Gizan) in Southern and Southwestern Saudi Arabia.…”