Children born in the United States are 6 times more likely to have tuberculosis (TB) if at least 1 parent was born abroad, according to a study published online February 10 in Pediatrics.
The finding prompted an accompanying editorial calling for the United States to help reduce TB infections in poorer countries.
"We cannot eradicate TB domestically until better TB control is attained in high-prevalence nations, especially those from which the United States receives many immigrants and visitors," write editorialists Jeffrey R. Starke, MD, and Andrea T. Cruz, MD, MPH, from the Department of Pediatrics, Baylor College of Medicine, Houston, Texas.
Previous studies have shown that more than 60% of US TB adult cases occur among foreign-born individuals and that 90% of pediatric cases occur among US-born children. Until now, however, no one has surveyed US children to see how their incidence of TB relates to either their country of origin or that of their parents.
To fill that gap, Jenny Pang, MD, MPH, from the Department of Epidemiology, University of Washington, Seattle, and colleagues from the Centers for Disease Control and Prevention and from other health departments and universities tallied TB diagnoses among children younger than 5 years in 20 catchment areas around the country. They identified 364 cases, which accounted for 49.6% of all TB cases in young children reported to the National Tuberculosis Surveillance System in 2005 and 2006.
In addition to using routine case reports and local health department data, the investigators conducted interviews with the children's parents or guardians to glean information about immigration.
They found that 303 (83%) children with TB were born in the United States and 61 (17%) were born outside of the United States. Of those born in the United States, 64% (194) had at least 1 foreign-born parent, 25% (76) had both parents born in the United States, and 11% (33) had parents whose birth countries were unknown.
The researchers then compared the incidence of TB with population figures for the catchment areas from the US Census. Rates of TB per 100,000 population in children younger than 5 years were 2.57 for all children, 24.03 for children who were born outside the United States, 4.81 for US-born children with at least a single foreign-born parent, and 0.75 for US children with both parents born in the United States.
Overall, more than half of the cases (53%) occurred among US-born children with 1 or more foreign-born parent. When the authors included the 33 children with unknown parental birthplaces in the group with foreign-born parents, that group's TB rate increased to 5.61 per 100,000 children. Including them in the group with US-born parents increased that group's rate to 1.08.
In an observational substudy, the researchers found that more than half of the parents were from Mexico, and nearly half of them reported being undocumented at the time of US entry. One-tenth of them expressed concerns that they or their children would be deported if they sought treatment for their child.
The editorialists argue that not enough attention is being paid to TB in the United States because of the mistaken perception that the disease is under control here.
They cite estimates from the World Health Organization that there were 530,000 cases of TB, with 74,000 deaths, among non-HIV-infected children worldwide in 2012. In addition, they note that previous estimates suggest every US dollar invested in TB programs in Mexico would save healthcare providers in the United States $3.
Therefore, they call for a campaign to eradicate TB by fully funding programs outlined in the Roadmap for Childhood Tuberculosis, a plan developed by the World Health Organization, the Centers for Disease Control and Prevention, and other US and international organizations.
The authors and editorialists have disclosed no relevant financial relationships.
Pediatrics. Published online February 10, 2014. Article abstract