Contrasting socioeconomic gradients in small for gestational age and preterm birth in Argentina, 2003–2007

Objectives

To examine the socioeconomic gradients in birth outcomes among singleton infants in Argentina, 2003–2007.

Methods

We analyzed data of 3,230,031 singleton infants born in 2003–2007, obtained from vital statistics. Associations between birth outcomes [small for gestational age (SGA), low birth weight (LBW), and preterm birth (PTB)] and socioeconomic indicators (maternal education and area-based material deprivation quintiles) were assessed with logistic regression.

Results

The risk of SGA increased with higher socioeconomic disadvantage, but that of PTB decreased. Compared to mothers who attained a tertiary or university degree, mothers who did not complete primary school were more likely to have a SGA infant [adjusted OR (95 % CI): 1.65 (1.62, 1.68)], but less likely to deliver preterm [0.92 (0.90, 0.94)]. As a result of the conflicting trends in SGA and PTB, LBW exhibited inconsistent socioeconomic gradients.

Conclusions

The excess risk of adverse birth outcomes associated with socioeconomic disadvantage was consistently reflected by SGA, but not by LBW and PTB. These findings challenge the usefulness of LBW as an indicator population health. Further research is needed to explain the reverse socioeconomic gradients in PTB.     

Low birthweight and prematurity in relation to paternal factors: a study of recurrence.

BACKGROUND: The importance of paternal determinants in the occurrence of low birthweight and prematurity is not well known. We investigated these outcomes in siblings and paternal half siblings as a function of changes in putative external determinants between two births in fathers who had experienced the birth of a premature and/or low birthweight (PTB/LBW) infant. METHODS: All fathers who, between 1980 and 1992, had an infant born before 37 completed weeks' gestation or weighing <2500 g and a following child were studied. We identified 14 147 pairs of siblings from Danish national registers. The recurrence risk was studied in three sub-cohorts defined by the outcome in the index child (PTB only, PTB/LBW, LBW only). We estimated the recurrence risk in the younger sibling according to changes of female partner, municipality type, occupation, and father's social status. RESULTS: The overall recurrence risk was 16.7% for preterm delivery and 16.8% for LBW. Changing female partner was, as expected, associated with a reduction in the recurrence risk for both outcomes (RR = 0.40; 95% CI: 0.27-0.60 for preterm delivery and RR = 0.38; 95% CI : 0.26-0.56 for LBW). None of the other studied factors was associated with changes in the recurrence risk. Fathers who changed partner had offspring with similar birthweight and gestational length between the three sub-cohorts, while a difference was evident in offspring to fathers whose female partner was unchanged. CONCLUSIONS: We did not identify any paternal factor of importance in the occurrence of LBW and preterm delivery.     

孕期职业紧张和不良生活事件对不同类型低体重儿的影响

目的 探讨孕期职业紧张和不良生活事件对匀称型和不匀称型低体重儿的影响.方法 选择438例低体重儿(匀称型337例,不匀称型101例)为病例组,438名正常新生儿为对照组,用多因素logistic回归分析控制产妇年龄、职业、文化程度和家庭月人均收入等因素后,分析孕期职业紧张和不良生活事件与两类低体重儿的关系.结果 职业紧张对孕期的影响显示,同技术使用程度低者相比,技术使用程度高的孕妇显著降低分娩匀称型(OR=0.69,95%CI:0.49～0.98)和不匀称型(OR=0.53,95%CI:0.31～0.89)低体重儿的危险性.与孕期未发生生活事件的孕妇相比,在整个孕期生活事件指数≥3分显著增加匀称型低体重儿的风险(OR=2.30,95%CI:1.08～4.88),在孕中期生活事件指数≥3分(OR=8.85,95% CI:1.97～39.68)、孕晚期生活事件指数≥3分(OR=3.80,95%CI:1.40～10.29)以及整个孕期生活事件指数2分(OR=3.58;95 % CI:1.33～9.66)和≥3分(OR=3.48,95% CI:1.32～9.13)显著增加非匀称型低体重儿的危险性.结论 孕期发生职业紧张和不良生活事件对不同类型低体重儿的发生产生影响,不同孕期发生的不良生活事件对不同类型低体重儿的影响存在差异.     

Birth weight trends among interracial black and white infants

I examined time trends in low birth weight (LBW) and very low birth weight (VLBW) among interracial compared with single-race infants. Using natality data from 1978 through 1997 for singleton births to black and white parents, I calculated relative risks (RRs) of LBW and VLBW for interracial compared with single-race births, stratified by maternal race and adjusted for maternal characteristics. Among black mothers, interracial births had lower risks of LBW and VLBW than single-race births, and RRs were similar throughout the time period [for example, adjusted RR = 0.76 and 95% confidence interval (CI) = 0.73-0.80 for LBW in 1994-1997]. Among white mothers, interracial infants had higher risks of LBW than single-race infants; however, the adjusted RRs declined over the time period, from 1.22 (95% CI = 1.19-1.27) in 1978-1981 to 1.05 (95% CI = 1.03-1.08) in 1994-1997. Since 1978, there has been some relative improvement in birth outcomes for infants of white mothers and black fathers compared with single-race white births. There was, however, no relative improvement for black mother/black father infants relative to black mother/white father births.     

Work with video display terminals and the risk of reduced birthweight and preterm birth

To determine whether the use of video display terminals (VDTs) is associated with an increased risk of reduced birthweight (RBW) and preterm birth, a cohort of telephone operators who used VDTs at work was compared to a cohort of non-VDT-users. Among 2,430 women interviewed, 713 eligible singleton live births were reported. Exposure was estimated from company records and a representative sample of electromagnetic fields was measured at the VDT workstations. For RBW (≤2,800 g), we found no excess risk associated with any VDT use during pregnancy (odds ratio [OR] = 0.9; 95% confidence interval [CI] = 0.5–1.7). For preterm birth (≤37 weeks), we similarly found no excess risk (OR = 0.7; 95%CI = 0.4–1.1). The risks estimated did not change substantially when hours working with VDTs were used as exposure variables. By contrast, increased risks were found for several known risk factors for LBW and preterm birth. We conclude that occupational VDT use does not increase the risk of RBW and preterm birth. Am. J. Ind. Med. 32:681–688, 1997. Published 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Chemical hair treatments and adverse pregnancy outcome among Black women in central North Carolina

Several studies suggest that toxic chemicals in hair products may be absorbed through the scalp in sufficient amounts to increase the risks of adverse health effects in women or their infants. This case-control study of 525 Black women from three counties in North Carolina who had delivered a singleton, liveborn infant examined whether exposure to chemicals used in hair straightening and curling increased the odds that the infant was preterm or low birth weight. Cases consisted of 188 preterm and 156 low birth weight births (for 123 women, their infant was both low birth weight and preterm). Controls were 304 women who delivered term and normal birth weight infants. Women who used a chemical hair straightener at any time during pregnancy or within 3 months prior to conception had an adjusted odds ratios (OR) of 0.7 (95% confidence interval (CI) 0.4-1.1) for preterm birth and 0.6 (95% CI 0.4-1.1) for low birth weight. Exposure to chemical curl products was also not associated with preterm delivery (adjusted OR = 0.9, 95% CI 0.5-1.8) or low birth weight (adjusted OR = 1.0, 95% CI 0.5-1.9). Despite this failure to find an association, continued search for risk factors to which Black women are uniquely exposed is warranted.     

Developing a Maternally Linked Birth Dataset to Study the Generational Recurrence of Low Birthweight in Virginia

This paper examined the generational recurrence of low birthweight (LBW) among first-born singletons using a statewide maternally-linked birth dataset. An intergenerational dataset was created by linking 2005–2009 to 1960–1997 Virginia resident live birth data. Maternal information from the recent birth cohort was linked to infant information in the historic birth file using various combinations of mother’s name and birthdate. The linked dataset contained 170,624 records (87 % of all eligible records). The analysis dataset was limited to non-Hispanic black and non-Hispanic white first-born singleton infants linked to their mother’s own birth record (n = 69,702). Maternal birthweight was a significant predictor of LBW for first-born singletons. The birthweight distribution for both non-Hispanic black and non-Hispanic white infants was shifted toward lower birthweights for infants whose mothers were born LBW. Even after adjusting for known maternal risk factors in the current pregnancy, non-Hispanic black (AOR = 1.6 [95 % CI 1.4, 1.8]) and non-Hispanic white (AOR = 2.0 [95 % CI 1.8, 2.3]) infants had increased odds of being born LBW if their mother was born LBW. A mother’s early life experiences can impact the health of her children. These findings underscore the importance of applying a life course perspective to the prevention of LBW. Routine linkage of maternal and infant birth data is needed to strengthen the evidence base for policies and programs that address issues affecting maternal and child health throughout the life course.     

Residential proximity to traffic and adverse birth outcomes in Los Angeles county,California, 1994-1996

We reported previously that increases in ambient air pollution in the Los Angeles basin increased the risk of low weight and premature birth. However, ambient concentrations measured at monitoring stations may not take into account differential exposure to pollutants found in elevated concentrations near heavy-traffic roadways. Therefore, we used an epidemiologic case-control study design to examine whether residential proximity to heavy-traffic roadways influenced the occurrence of low birth weight (LBW) and/or preterm birth in Los Angeles County between 1994 and 1996. We mapped subject home locations at birth and estimated exposure to traffic-related air pollution using a distance-weighted traffic density (DWTD) measure. This measure takes into account residential proximity to and level of traffic on roadways surrounding homes. We calculated odds ratios (ORs) and risk ratios (RRs) for being LBW and/or preterm per quintile of DWTD. The clearest exposure-response pattern was observed for preterm birth, with an RR of 1.08 [95% confidence interval (CI), 1.01-1.15] for infants in the highest DWTD quintile. Although higher risks were observed for LBW infants, exposure-response relations were less consistent. Examining the influence of season, we found elevated risks primarily for women whose third trimester fell during fall/winter months (OR(term LBW) = 1.39; 95% CI, 1.16-1.67; OR(preterm and LBW) = 1.24; 95% CI = 1.03-1.48; RR(all preterm) = 1.15; 95% CI, 1.05-1.26), and exposure-response relations were stronger for all outcomes. This result is consistent with elevated pollution in proximity to sources during more stagnant air conditions present in winter months. Our previous research and these latest results suggest exposure to traffic-related pollutants may be important.     

Risk factors for the increasing trend in low birth weight among live births born by vaginal delivery, Brazil

OBJECTIVE: To identify risk factors for low birth weight (LBW) among live births by vaginal delivery and to determine if the disappearance of the association between LBW and socioeconomic factors was due to confounding by cesarean section. METHODS: Data were obtained from two population-based cohorts of singleton live births in Ribeir?o Preto, Southeastern Brazil. The first one comprised 4,698 newborns from June 1978 to May 1979 and the second included 1,399 infants born from May to August 1994. The risks for LBW were tested in a logistic model, including the interaction of the year of survey and all independent variables under analysis. RESULTS: The incidence of LBW among vaginal deliveries increased from 7.8% in 1978--79 to 10% in 1994. The risk was higher for: female or preterm infants; newborns of non-cohabiting mothers; newborns whose mothers had fewer prenatal visits or few years of education; first-born infants; and those who had smoking mothers. The interaction of the year of survey with gestational age indicated that the risk of LBW among preterm infants fell from 17.75 to 8.71 in 15 years. The mean birth weight decreased more significantly among newborns from qualified families, who also had the highest increase in preterm birth and non-cohabitation. CONCLUSIONS: LBW among vaginal deliveries increased mainly due to a rise in the proportion of preterm births and non-cohabiting mothers. The association between cesarean section and LBW tended to cover up socioeconomic differences in the likelihood of LBW. When vaginal deliveries were analyzed independently, these socioeconomic differences come up again.     

Maternal occupation and adverse pregnancy outcomes: a Finnish population-based study

BACKGROUND: There is accumulating evidence that the type of work and environmental exposures in the working environment may have adverse effects on foetal development. AIM: To compare the risk of low birth weight (LBW), small-for-gestational age (SGA) and pre-term delivery (PD) in broad categories of maternal occupation including farming and forestry; factory, mining and construction; office, non-manual and service work and housewives. METHODS: The study population consisted of 2568 singleton newborns of women who participated in The Finnish Prenatal Environment and Health Study after the delivery (response rate 94%). Information on maternal occupation and work during pregnancy was collected after the delivery. The health outcomes were LBW (<2500 g), SGA and PD (<37 weeks). RESULTS: In newborns of women working in factories, mining and construction, the risk of LBW (adjusted odds ratio [OR] 3.66, 95% confidence interval [CI] 1.15-11.62), SGA (adjusted OR 1.53, 95% CI 0.73-3.21), but not the risk of PD (adjusted OR 0.64, 95% CI 0.19-2.22), was higher compared with newborns of housewives. In newborns of farmers and forestry workers, the risks of PD (adjusted OR 2.38, 95% CI 1.01-5.65), LBW (adjusted OR 2.86, 95% CI 0.78-11.58) and SGA (adjusted OR 1.51, 95% CI 0.62-3.65) were all elevated. In office, non-manual and service workers, the corresponding estimates were lower (LBW: 1.62, 0.67-3.95; SGA: 1.45, 0.92-2.28; PD: 1.18, 0.69-2.01). CONCLUSIONS: There were substantial differences in the risk of adverse pregnancy outcomes between the main branches of industry.     

Impact of reduced maternal exposures to wood smoke from an introduced chimney stove on newborn birth weight in rural Guatemala

Background: A growing body of evidence indicates a relationship between household indoor air pollution from cooking fires and adverse neonatal outcomes, such as low birth weight (LBW), in resource-poor countries.Objective: We examined the effect of reduced wood smoke exposure in pregnancy on LBW of Guatemalan infants in RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects).Methods: Pregnant women (n = 266) either received a chimney stove (intervention) or continued to cook over an open fire (control). Between October 2002 and December 2004 we weighed 174 eligible infants (69 to mothers who used a chimney stove and 105 to mothers who used an open fire during pregnancy) within 48 hr of birth. Multivariate linear regression and adjusted odds ratios (ORs) were used to estimate differences in birth weight and LBW (< 2,500 g) associated with chimney-stove versus open-fire use during pregnancy.Results: Pregnant women using chimney stoves had a 39% reduction in mean exposure to carbon monoxide compared with those using open fires. LBW prevalence was high at 22.4%. On average, infants born to mothers who used a stove weighed 89 g more [95% confidence interval (CI), –27 to 204 g] than infants whose mothers used open fires after adjusting for maternal height, diastolic blood pressure, gravidity, and season of birth. The adjusted OR for LBW was 0.74 (95% CI, 0.33–1.66) among infants of stove users compared with open-fire users. Average birth weight was 296 g higher (95% CI, 109–482 g) in infants born during the cold season (after harvest) than in other infants; this unanticipated finding may reflect the role of maternal nutrition on birth weight in an impoverished region.Conclusions: A chimney stove reduced wood smoke exposures and was associated with reduced LBW occurrence. Although not statistically significant, the estimated effect was consistent with previous studies.     

The “Latina Epidemiologic Paradox”: Contrasting Patterns of Adverse Birth Outcomes in U.S.-Born and Foreign-Born Latinas

BackgroundThe “Latina epidemiologic paradox” postulates that despite socioeconomic disadvantages, Latina mothers have a lower risk for delivering low birth weight (LBW) babies than non-Latina Whites. However, these patterns may be changing over time and may differ depending on the mother's birthplace and legal status in the United States. This study investigates differences in risk for three birth outcomes among Whites, U.S.-born Latinas, and foreign-born Latinas.MethodsWe undertook a cross-sectional study of rates of LBW, preterm, and small-for-gestational-age (SGA) births among 196,617 women delivering live, singleton births in Utah from 2004 to 2007. Each group was compared using logistic regression.ResultsU.S.-born Latinas had a similar or greater risk for all three outcomes when compared with Whites. Foreign-born Latinas had lower risk for preterm birth (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.80–0.90) compared with Whites, but not for LBW and SGA; foreign-born Latinas had a lower risk for LBW (OR, 0.82; 95% CI, 0.74–0.92), preterm birth (OR, 0.81; 95% CI, 0.74–0.89), and SGA (OR, 0.91; 95% CI, 0.83–0.99) compared with U.S.-born Latinas. Among foreign-born Latinas only, there was no difference in risk between documented (i.e., those who had a legal social security number) and undocumented women for LBW, preterm birth, or SGA.ConclusionsThese data support the existence of a variation of the “Latina paradox” among Latinas according to birthplace, where U.S.-born Latinas do not experience better birth outcomes than Whites, but foreign-born Latinas experience better birth outcomes for several endpoints compared with U.S.-born Latinas. Prevention efforts may prove more effective by considering the different composition of risk factors among foreign- and U.S.-born Latina populations.     

The perinatal advantage of Mexican-origin Latina women

PURPOSE: To determine if there is a perinatal advantage for birth outcomes among Mexican-origin Latina (Latina) women compared to white non-Hispanic (white) women, after adjusting for maternal, paternal, and infant factors.

METHODS: 1,439,583 births from the 1990–1993 California linked birth and infant death certificate data sets were analyzed for the risk of low birth weight infants and infant mortality.

RESULTS: Latina women had a statistically higher unadjusted risk of low birth weight infants and infant mortality compared to white women. After adjusting for potential confounders, Latina women had a similar risk of low birth weight infants and a lower risk of infant mortality relative to white women. In multivariate analyses, the most significant risk factor for low infant birth weight was young gestational age (OR = 82.91 for gestational age 1–230 days and OR = 10.62 for gestational age 231–258 days) and the most significant risk factor for infant mortality was low birth weight (OR = 53.99 for infant birth weight <500 grams and OR = 9.27 for infant birth weight 500–2499 grams).

CONCLUSION: There was some evidence of a perinatal advantage for Latina women, when compared to white women and after adjusting for numerous potential confounders. To further reduce the risk of low birth weight infants and infant mortality, additional research is needed for etiologic clues beyond race/ethnicity and other traditional risk factors.     

母亲孕期被动吸烟烟及父亲饮酒与低出生体重儿关系研究

目的：为进一步探索低出生体重儿发生的相关危险因素。方法：我们对沈阳市妇婴等15家医院分娩的部分产妇进行了低出生体重儿的病例对照研究。结果：在控制孕妇患慢性疾病、生殖器官的畸形、严重妊娠反应、文化程度、巨细胞病毒等感染以及主动吸烟等混杂因素后,孕期被动吸烟分娩出低出生体重儿的危险性为非被动吸烟的2.95倍,95%可信区间OR95%CI为2.07-4.21;丈夫饮酒史、自然流产、人工流产史、家族低体重史、孕前的BMI、孕期服用解热镇痛药物以及职业接触有机物均可能是低出生体重儿的危险因素。     

孕前体质指数及孕期增重对新生儿出生体重影响的前瞻性队列研究

  目的   分析孕妇孕前体质指数(body mass index, BMI)及孕期增重(gestational weight gain, GWG)与新生儿出生体重的关联性, 并探究孕妇孕前及孕中体重动态变化对新生儿低出生体重(low birth weight, LBW)及巨大儿的影响。   方法   收集中国孕产妇队列·协和纳入的孕早期孕妇孕前体重, 并随访至分娩后, 收集分娩前体重及新生儿出生结局。将孕妇孕前BMI分为低体重组、正常体重组及超重/肥胖组, 将GWG分为适宜、不足及过多组。采用多因素多分类(多项)Logistic回归分析模型探讨孕前BMI及GWG与新生儿出生体重的关系。   结果   孕前BMI及GWG与子代出生体重相关(均有P < 0.05)。孕前超重/肥胖(OR=2.339, 95% CI:1.674~2.282, P < 0.001)、GWG过多(OR=1.398, 95% CI:1.188~1.978, P=0.048)显示为巨大儿的危险因素, GWG不足(OR=1.479, 95% CI:1.461~1.679, P=0.035)显示为LBW的危险因素, GWG过多会降低LBW的发生风险(OR=0.428, 95% CI:0.225~0.817, P=0.010)。低BMI-GWG不足(OR=1.335, 95% CI:1.048~2.319, P=0.048)是LBW的危险因素; 正常BMI-GWG过多(OR=1.088, 95% CI:1.016~1.675, P=0.038)和超重/肥胖-GWG过多(OR=1.498, 95% CI:1.244~2.017, P=0.046)是巨大儿的危险因素。   结论   孕前BMI及GWG是影响新生儿出生体重的重要因素, 提示女性应合理控制孕前及孕中体重变化。     

Risk of low birthweight and prematurity among foreign-born mothers.

Data collected during postnatal visits were used to study the risk of low birthweight (LBW) and prematurity among foreign-born mothers and mothers born in Canada. 2,913 singleton live births were included in the analysis. Odds ratios (OR) and 95% confidence intervals (CI) for LBW and prematurity were estimated using a logistic regression model. Foreign-born mothers did not have a higher risk of LBW or prematurity as compared to native-born mothers (OR = 1.1, 95% CI = 0.8-1.5; OR = 1.0, 95% CI = 0.7-1.4, respectively). For both LBW and prematurity, women in the intermediate category of length of stay (1-3 years) had a somewhat lower risk and women with the shortest length of stay (less than one year) had a slightly higher risk than women with the longest length of stay (more than 3 years). However, none of these results was statistically significant. Results of this study suggest that foreign-born mothers do not have a higher risk than Canadian-born mothers of bearing a LBW or premature infant. This finding differs from the widespread perception that immigrant mothers are at high risk for adverse birth outcomes.     

孕期职业应激和不良生活事件与低体重儿的关系

目的 探讨孕期职业应激和不良生活事件对低体重儿的影响.方法 以某省2家妇幼保健院出生的孕周≥28周且<42周、体重<2500 g的单胎、活产、无畸形的438例低体重儿为病例组,按1:1匹配的原则,选择同一家医院分娩、新生儿同性别、分娩时间不超过1周的438例足月正常体重儿为对照组,进行病例对照研究.由培训合格的调查员对其母亲进行调查,内容包括产妇一般情况、职业应激和孕期不良生活事件等.在控制产妇年龄、职业、文化程度和家庭月人均收入等因素后,应用条件logisfic回归探讨孕期职业应激和不良生活事件对低体重儿的影响.结果 与低技术使用度和低工作决策相比,拥有高技术使用度(OR=0.62;95%CI=0.43～0.91)和高工作决策(OR=0.67;95%CI=0.46～0.97)可明显降低低体重儿的危险性.与孕期未发生生活事件的孕妇相比,在孕中期生活事件指数3分及以上(OR:18.85:95%CI=1.58～225.02)、孕晚期生活事件指数1分(OR=2.67;95%CI=1.14～6.28)、整个孕期生活事件指数2分(OR=2.80;95%CI=1.04～7.52)和≥3分(OR=2.94;95%CI=1.22-7.09)是低体重儿的危险因素.结论 孕期发生不良生活事件可影响低体重儿的发生,且不同孕期发生的不良生活事件对低体重儿的影响存在差异.     

The association of change in maternal marital status between births and adverse pregnancy outcomes in the second birth

The relationships between change in marital status between two consecutive births and adverse pregnancy outcomes at the second birth were investigated using linked Washington State 1980–93 white singleton birth certificates. Women who were married at the first birth had lower low birthweight (LBW) and small-size-for-gestational-age (SGA) rates at that birth than single women, and women married at the second birth had lower LBW, SGA and preterm delivery rates at that birth, regardless of marital status at the first birth. Adjusted relative risks (RR) of LBW and SGA were significantly increased for initially married women who were single at the second birth compared with those who remained married (RR equals; 1.4 and 1.3, respectively). Risks of LBW and SGA were significantly decreased among initially single women who married by the second birth, compared with those remaining single (RR equals; 0.7 for LBW and 0.8 for SGA). We conclude that the largely unstudied subgroup of previously married women is at increased risk for adverse pregnancy outcomes. Public health policy and programmes directed at high-risk mothers and infants should be aware of the specific physical and emotional needs of this group of child-bearing women.     

The “Latina Epidemiologic Paradox” Revisited: The Role of Birthplace and Acculturation in Predicting Infant Low Birth Weight for Latinas in Los Angeles, CA

The "Latina epidemiologic paradox" refers to the observation that despite socioeconomic disadvantages, Latina mothers in the United States (US) have a similar or lower risk for delivering an infant with low birth weight (LBW) compared to non-Latina White mothers. An analogous paradox may exist between foreign-born (FB) and US-born (USB) Latinas. Our goal was to assess differences in LBW in USB Latinas, FB Latinas, and non-Latina Whites in Los Angeles County in 2003 using birth records and survey data. Using logistic regression, we estimated associations between LBW and birthplace/ethnicity in a birth cohort and nested survey responder group and between LBW and acculturation in responders to a follow-up survey. USB Latinas and FB Latinas had a higher prevalence of LBW infants compared to Whites (odds ratio [OR]?=?1.34, 95% confidence interval [CI]?=?(1.17, 1.53) and OR?=?1.32, 95% CI?=?(1.18, 1.49), respectively); when we adjusted for additional maternal risk factors these point estimates were attenuated, and interval estimates were consistent with a modest positive or inverse association. Among Latinas only, LBW was more common for high-acculturated FB and USB Latinas compared to low-acculturated FB Latinas, and there was limited evidence that environmental or behavior risk factors had less impact in low-acculturated Latinas. In summary, adjusting only for demographics, Latinas in our study were more likely to have LBW infants compared to Whites, in contrast to the Latina paradox hypothesis. Furthermore, adjusting for environmental or behavioral factors attenuated the positive association, but there was little evidence that Latinas had a lower prevalence of LBW regardless of the variables included in the models. Finally, among Latinas, there was limited evidence that associations between known risk factors and LBW were modified by acculturation.     

Ambient air pollution and apnea and bradycardia in high-risk infants on home monitors

Background: Evidence suggests that increased ambient air pollution concentrations are associated with health effects, although relatively few studies have specifically examined infants.Objective: We examined associations of daily ambient air pollution concentrations with central apnea (prolonged pauses in breathing) and bradycardia (low heart rate) events among infants prescribed home cardiorespiratory monitors.Methods: The home monitors record the electrocardiogram, heart rate, and respiratory effort for detected apnea and bradycardia events in high-risk infants [primarily premature and low birth weight (LBW) infants]. From August 1998 through December 2002, 4,277 infants had 8,960 apnea event-days and 29,450 bradycardia event-days in > 179,000 days of follow-up. We assessed the occurrence of apnea and bradycardia events in relation to speciated particulate matter and gaseous air pollution levels using a 2-day average of air pollution (same day and previous day), adjusting for temporal trends, temperature, and infant age.Results: We observed associations between bradycardia and 8-hr maximum ozone [odds ratio (OR) = 1.049 per 25-ppb increase; 95% confidence interval (CI), 1.021–1.078] and 1-hr maximum nitrogen dioxide (OR =1.025 per 20-ppb increase; 95% CI, 1.000–1.050). The association with ozone was robust to different methods of control for time trend and specified correlation structure. In secondary analyses, associations of apnea and bradycardia with pollution were generally stronger in infants who were full term and of normal birth weight than in infants who were both premature and LBW.Conclusions: These results suggest that higher air pollution concentrations may increase the occurrence of apnea and bradycardia in high-risk infants.