Hematological, immunological, and cardiovascular changes in individuals residing in a polluted city of India: a study in Delhi.

Exposure to poor air quality is associated with a multitude of hematological and immunological alterations. Cardio vascular diseases, rather than respiratory ailments, are the most important cause of death from air pollution exposure. Thus, hematological, immunological and cardiovascular alterations in healthy individuals exposed to vehicular pollution (one of the leading source of air pollution in growing metropolitan cities) are investigated in this study. A total number of 2218 (21-65 years old) adults residing in Delhi participated in this study. As control, 642 age and sex matched healthy subjects from the rural areas of Uttaranchal were enrolled. Arterial blood pressure (BP) was measured by a sphygmomanometer. Blood samples were collected and routine hematology was done. Lymphocyte subset analysis and platelet P-selectin expression was measured by flow cytometry. Air quality data was collected from Central and State Pollution Control Boards and was also measured onsite by portable, battery-operated laser photometer. The prevalence of hypertension was nearly 4-times higher in Delhi when compared to the control. Platelet P-selectin was remarkably upregulated in residents of Delhi. They had depleted number of CD4+ T-helper cells and CD19+ B cells but elevated level of CD56+ natural killer cells. Altered lymphocyte subtypes and increased number of P-selectin-positive platelets suggest altered immunity (that may compromise body's defense against infections) and hypercoagulable state, a risk factor for cardiovascular diseases. The current study has identified poor air quality of Delhi as a key contributor to several adverse health conditions experienced by the general population of the city, which not only makes the quality of life compromised but also put them at a greater risk of developing cardiovascular ailments later in life.