Preterm Birth Risk Linked to Longer Residence in U.S.

DALLAS – Preterm birth may be related in part to potentially preventable environmental factors, data from the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2006 suggest.

Survey responses from 2,441 Hispanic women with a prior live birth show that the rate of births prior to 36 weeks’ gestation in Hispanic immigrants who resided in the United States for less than 10 years was 3.1%, which was significantly lower than the 7.4% rate among those who lived in the United States for more than 10 years, and the 10.1% rate among Hispanic women born in the United States (age adjusted odds ratios, 2.1 and 3.1, respectively), Dr. Radek Bukowski reported at the annual meeting of the Society for Maternal-Fetal Medicine.

The findings were similar after further adjustment for numerous factors that might affect preterm birth risk, such as age, body mass index, education, nutrition, marital status, sexual behaviors, toxic exposures, income, smoking status, diabetes, and hypertension (fully adjusted odds ratios, 2.1 and 3.5), said Dr. Bukowski of the University of Texas Medical Branch at Galveston.

One factor – language spoken at home – did appear to have a modifying effect on the association between length of residence in the United States and the risk of preterm birth, however.

"Compared with women who lived in the United States less than 10 years, those who lived here 10 years or longer and those who were born in the United States had the highest risk if they predominantly or exclusively spoke Spanish at home," Dr. Bukowski said.

Also, body mass index was negatively associated with preterm birth, and hypertension was positively associated with preterm birth, but these were not found to be independent risk factors in the fully adjusted model, he said.

Although nongenetic environmental factors have been thought to play a role in preterm birth risk, it has not been clear whether risk is predominantly related to genetic or environmental factors. However, many immigrants are known to have a lower risk, which could be related to better diet and health status, he said.

Although limited by the study’s cross-sectional design, the current findings suggest that risk is acquired with residence in the United States. Given this, as well as the fact that preterm birth was not associated with a number of other risk factors in this study, it is possible that the level of risk is modifiable, Dr. Bukowski concluded.

Dr. Bukowski said he had no relevant financial disclosures.

DALLAS – Preterm birth may be related in part to potentially preventable environmental factors, data from the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2006 suggest.

Survey responses from 2,441 Hispanic women with a prior live birth show that the rate of births prior to 36 weeks’ gestation in Hispanic immigrants who resided in the United States for less than 10 years was 3.1%, which was significantly lower than the 7.4% rate among those who lived in the United States for more than 10 years, and the 10.1% rate among Hispanic women born in the United States (age adjusted odds ratios, 2.1 and 3.1, respectively), Dr. Radek Bukowski reported at the annual meeting of the Society for Maternal-Fetal Medicine.

The findings were similar after further adjustment for numerous factors that might affect preterm birth risk, such as age, body mass index, education, nutrition, marital status, sexual behaviors, toxic exposures, income, smoking status, diabetes, and hypertension (fully adjusted odds ratios, 2.1 and 3.5), said Dr. Bukowski of the University of Texas Medical Branch at Galveston.

One factor – language spoken at home – did appear to have a modifying effect on the association between length of residence in the United States and the risk of preterm birth, however.

"Compared with women who lived in the United States less than 10 years, those who lived here 10 years or longer and those who were born in the United States had the highest risk if they predominantly or exclusively spoke Spanish at home," Dr. Bukowski said.

Also, body mass index was negatively associated with preterm birth, and hypertension was positively associated with preterm birth, but these were not found to be independent risk factors in the fully adjusted model, he said.

Although nongenetic environmental factors have been thought to play a role in preterm birth risk, it has not been clear whether risk is predominantly related to genetic or environmental factors. However, many immigrants are known to have a lower risk, which could be related to better diet and health status, he said.

Although limited by the study’s cross-sectional design, the current findings suggest that risk is acquired with residence in the United States. Given this, as well as the fact that preterm birth was not associated with a number of other risk factors in this study, it is possible that the level of risk is modifiable, Dr. Bukowski concluded.

Dr. Bukowski said he had no relevant financial disclosures.

DALLAS – Preterm birth may be related in part to potentially preventable environmental factors, data from the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2006 suggest.

Survey responses from 2,441 Hispanic women with a prior live birth show that the rate of births prior to 36 weeks’ gestation in Hispanic immigrants who resided in the United States for less than 10 years was 3.1%, which was significantly lower than the 7.4% rate among those who lived in the United States for more than 10 years, and the 10.1% rate among Hispanic women born in the United States (age adjusted odds ratios, 2.1 and 3.1, respectively), Dr. Radek Bukowski reported at the annual meeting of the Society for Maternal-Fetal Medicine.

The findings were similar after further adjustment for numerous factors that might affect preterm birth risk, such as age, body mass index, education, nutrition, marital status, sexual behaviors, toxic exposures, income, smoking status, diabetes, and hypertension (fully adjusted odds ratios, 2.1 and 3.5), said Dr. Bukowski of the University of Texas Medical Branch at Galveston.

One factor – language spoken at home – did appear to have a modifying effect on the association between length of residence in the United States and the risk of preterm birth, however.

"Compared with women who lived in the United States less than 10 years, those who lived here 10 years or longer and those who were born in the United States had the highest risk if they predominantly or exclusively spoke Spanish at home," Dr. Bukowski said.

Also, body mass index was negatively associated with preterm birth, and hypertension was positively associated with preterm birth, but these were not found to be independent risk factors in the fully adjusted model, he said.

Although nongenetic environmental factors have been thought to play a role in preterm birth risk, it has not been clear whether risk is predominantly related to genetic or environmental factors. However, many immigrants are known to have a lower risk, which could be related to better diet and health status, he said.

Although limited by the study’s cross-sectional design, the current findings suggest that risk is acquired with residence in the United States. Given this, as well as the fact that preterm birth was not associated with a number of other risk factors in this study, it is possible that the level of risk is modifiable, Dr. Bukowski concluded.

Dr. Bukowski said he had no relevant financial disclosures.