The following covariates were considered in this analysis: household size modeled as a categorical variable (categories), marital status (categories), race and ethnicity (categories),
maternal age modeled as a categorical variable (categories), parity (categories), education (categories), employment status (categories), maternal occupation (categories), and postnatal WIC participation.
Not exact matches
All
models were adjusted for potential confounders, including
maternal education, ethnicity, smoking, gestational
age, birth weight, siblings, and day care attendance.
We used multivariable logistic - regression
models to adjust for potential confounders, including
maternal race or ethnic group (non-Hispanic white vs. other), parity (nulliparous vs. multiparous), insurance status (public or none vs. other), extent of prenatal care (≥ 5 visits vs. < 5 visits), advanced
maternal age (≥ 35 years vs. < 35 years),
maternal education (> 12 years vs. ≤ 12 years), history or no history of cesarean delivery, and a composite marker of conditions that confer increased medical risk.
To assess the robustness of the results of our regression analysis, we performed covariate adjustment with derived propensity scores to calculate the absolute risk difference (details are provided in the Supplementary Appendix, available with the full text of this article at NEJM.org).14, 15 To calculate the adjusted absolute risk difference, we used predictive margins and G - computation (i.e., regression -
model — based outcome prediction in both exposure settings: planned in - hospital and planned out - of - hospital birth).16, 17 Finally, we conducted post hoc analyses to assess associations between planned out - of - hospital birth and outcomes (cesarean delivery and a composite of perinatal morbidity and mortality), which were stratified according to parity,
maternal age,
maternal education, and risk level.
All the
models were adjusted for
maternal race or ethnic group, parity, insurance status (for cesarean delivery), extent of prenatal care,
maternal age and education, history of cesarean delivery, and a composite of
maternal conditions associated with an increased medical risk (chronic hypertension, gestational hypertension, preeclampsia, eclampsia, prepregnancy diabetes, or gestational diabetes).
Of note, our
models may underestimate the true
maternal costs of suboptimal breastfeeding; we
modeled the effects of lactation on only five
maternal health conditions despite data linking lactation with other
maternal health outcomes.46 In addition, women in our
model could not develop type 2 diabetes mellitus, hypertension, or MI before
age 35 years, although these conditions are becoming increasingly prevalent among young adults.47 Although some studies have found an association between lactation and rates of postmenopausal diabetes22, 23 and cardiovascular disease, 10 we conservatively limited the duration of lactation's effect on both diabetes and MI.
We used multiple regression to estimate the differences in total cost between the settings for birth and to adjust for potential confounders, including
maternal age, parity, ethnicity, understanding of English, marital status, BMI, index of multiple deprivation score, parity, and gestational
age at birth, which could each be associated with planned place of birth and with adverse outcomes.12 For the generalised linear
model on costs, we selected a γ distribution and identity link function in preference to alternative distributional forms and link functions on the basis of its low Akaike's information criterion (AIC) statistic.
Other
maternal variables tested in the
model included
maternal age, ethnic group, socioeconomic status, parity, prepregnancy weight and height, CES - D score, and use of tobacco.
Once the final additive
model was built, interaction terms were tested, involving intended place of birth and: pregnancy risk factors, year, parity,
maternal age and time of birth.
When logistic
models were stratified by the presence or absence of hypertensive disease, only
maternal age older than 34 years (odds ratio [OR], 1.4; 95 % confidence interval [CI], 1.0 - 2.0), pregnancy - associated plasma protein - A of the 95th percentile or less (OR, 1.9; 95 % CI, 1.2 - 3.1), and alpha fetoprotein of the 95th percentile or greater (OR, 2.3; 95 % CI, 1.4 - 3.8) remained statistically significantly associated for abruption.In this large, population - based cohort study, abnormal
maternal aneuploidy serum analyte levels were associated with placental abruption, regardless of the presence of hypertensive disease.
Model 1 adjusted for covariates in model 0 plus gestational age and birth weight z score.18 Model 2 adjusted for covariates in model 1 plus child race / ethnicity and maternal age, parity, smoking status, depression at 6 months» post partum, and employment and child care at age 6 months, as well as primary language, annual household income, and parental educational level and marital st
Model 1 adjusted for covariates in
model 0 plus gestational age and birth weight z score.18 Model 2 adjusted for covariates in model 1 plus child race / ethnicity and maternal age, parity, smoking status, depression at 6 months» post partum, and employment and child care at age 6 months, as well as primary language, annual household income, and parental educational level and marital st
model 0 plus gestational
age and birth weight z score.18
Model 2 adjusted for covariates in model 1 plus child race / ethnicity and maternal age, parity, smoking status, depression at 6 months» post partum, and employment and child care at age 6 months, as well as primary language, annual household income, and parental educational level and marital st
Model 2 adjusted for covariates in
model 1 plus child race / ethnicity and maternal age, parity, smoking status, depression at 6 months» post partum, and employment and child care at age 6 months, as well as primary language, annual household income, and parental educational level and marital st
model 1 plus child race / ethnicity and
maternal age, parity, smoking status, depression at 6 months» post partum, and employment and child care at
age 6 months, as well as primary language, annual household income, and parental educational level and marital status.
Matching variables (
maternal race / ethnicity, infant
age at last sleep, birth year, and region) were included in all the
models.
Models were developed using the following possible predictors of breastfeeding duration:
maternal race,
maternal education, paternal education,
maternal age, socioeconomic status, 22 marital status, parity, mode of delivery, previous breastfeeding experience, timing of feeding method selection, problems with pregnancy / labor / delivery, breastfeeding goal (weeks), family preference for breastfeeding, paternal preference for breastfeeding, having friends who breastfed, randomization group, 16 plans to return to work, infant's 5 - minute Apgar score, and infant's
age in minutes when first breastfed (first successful latch and feeding).
To facilitate presentation of the final
model, dichotomous variables were constructed for these factors (ie, goal ≤ 26 weeks or > 26 weeks and
maternal age ≤ 30 years or > 30 years).
Among the
maternal anthropometric (dimension 2) variables, only greater BMI was associated with delayed OL, and this relation remained significant in a
model adjusted for
maternal age.
In a multivariate
model adjusted for prenatal feeding intentions, independent risk factors for delayed OL were
maternal age ≥ 30 y, body mass index in the overweight or obese range, birth weight > 3600 g, absence of nipple discomfort between 0 — 3 d postpartum, and infant failing to «breastfeed well» ≥ 2 times in the first 24 h. Postpartum edema was significant in an alternate
model excluding body mass index (P < 0.05).
However, in a
model adjusted for all 3 of these characteristics, only
maternal age (≥ 30 y) remained a significant risk factor (P < 0.05).
Despite collinearity between
maternal age, BMI, and infant birth weight, all 3 variables were independently associated with delayed OL in a multivariate
model.
The addition of the Infant Feeding Intentions score to the
model strengthened the association with
maternal age and BMI, with little effect on the other variables.
Among newborn characteristics (dimension 4), higher birth weight and lower 1 - min Apgar score were associated with delayed OL; birth weight > 3600 g remained a significant risk factor in a
model adjusted for
maternal age and BMI.
Modeling was used in the evaluation of initiation, duration,
maternal age, income, household composition, employment, marital status, postpartum depression, preterm birth, smoking, belief that «breast is best,» family history of breastfeeding, and in - hospital formula introduction.
These
models allowed us to evaluate the association between individual task score and program outcome after adjustment for important confounders (breed,
maternal parity, sex of puppy, and
age at return).
We built a generalized estimating equation (GEE) general linear
model (GLM) with outcome as the dependent variable; time in the nursing box, licking / grooming per puppy, vertical nursing per puppy, and ventral nursing per puppy were entered as predictors with breed,
maternal parity, sex of puppy, and
age at return entered as covariates.
21, 36, 37), breed,
maternal parity (1 — 5), sex of puppy (1/0, male vs. female), litter size (2 — 10 puppies), and
age in months (14 — 17) when the dog returned for training were included as covariates in all
models.
The effect of
maternal care and
age of separation (from the mother) on TC was also evaluated using a generalized linear
model with a binomial distribution.
The Patient Protection and Affordable Care Act allocated $ 1.5 billion annually for the
Maternal, Infant, and Early Childhood Home Visiting Program (MIECHV) to fund states in implementing home visiting program
models for families with children from birth to
age 5 as well as pregnant women.
An interaction term between
maternal education and
age was included in the
model in order to estimate PDs and PRs at
age 3, 5, 7 and 11 years.
Population average
models were used to account for the longitudinal study design and correlation of repeated measurements, and an interaction term between
maternal education (our socioeconomic measure) and
age was included in order to examine whether differences in health inequalities by
age were statistically significant.
Finally, we examined the association between sociodemographic variables (child
age, sex, race / ethnicity,
maternal obesity,
maternal education, poverty) and prevalence of having a chronic condition during any part of the 6 - year study period in multivariate logistic regression
models that included all participants.
We tested the role of
maternal depression at 36 months (as measured by the continuous CIDI - SF scale) as a mediator of the relation between both chronic
maternal IPV and
maternal IPV prior to 36 months and obesity risk at
age 60 months in separate
models using the Preacher and Hayes bootstrapping method.49 We found evidence for simple mediation of
maternal IPV prior to 36 months and chronic
maternal IPV by
maternal depression.
Models adjusted for child's
age, sex, race / ethnicity,
maternal education, economic hardship, tobacco exposure, and low birth weight.
A covariate was included in the multivariate analyses if theoretical or empirical evidence supported its role as a risk factor for obesity, if it was a significant predictor of obesity in univariate regression
models, or if including it in the full multivariate
model led to a 5 % or greater change in the OR.48 Model 1 includes maternal IPV exposure, race / ethnicity (black, white, Hispanic, other / unknown), child sex (male, female), maternal age (20 - 25, 26 - 28, 29 - 33, 34 - 50 years), maternal education (less than high school, high school graduation, beyond high school), maternal nativity (US born, yes or no), child age in months, relationship with father (yes or no), maternal smoking during pregnancy (yes or no), maternal depression (as measured by a CIDI - SF cutoff score ≥ 0.5), maternal BMI (normal / underweight, overweight, obese), low birth weight (< 2500 g, ≥ 2500 g), whether the child takes a bottle to bed at age 3 years (yes or no), and average hours of child television viewing per day at age 3 years (< 2 h / d, ≥ 2 h
model led to a 5 % or greater change in the OR.48
Model 1 includes maternal IPV exposure, race / ethnicity (black, white, Hispanic, other / unknown), child sex (male, female), maternal age (20 - 25, 26 - 28, 29 - 33, 34 - 50 years), maternal education (less than high school, high school graduation, beyond high school), maternal nativity (US born, yes or no), child age in months, relationship with father (yes or no), maternal smoking during pregnancy (yes or no), maternal depression (as measured by a CIDI - SF cutoff score ≥ 0.5), maternal BMI (normal / underweight, overweight, obese), low birth weight (< 2500 g, ≥ 2500 g), whether the child takes a bottle to bed at age 3 years (yes or no), and average hours of child television viewing per day at age 3 years (< 2 h / d, ≥ 2 h
Model 1 includes
maternal IPV exposure, race / ethnicity (black, white, Hispanic, other / unknown), child sex (male, female),
maternal age (20 - 25, 26 - 28, 29 - 33, 34 - 50 years),
maternal education (less than high school, high school graduation, beyond high school),
maternal nativity (US born, yes or no), child
age in months, relationship with father (yes or no),
maternal smoking during pregnancy (yes or no),
maternal depression (as measured by a CIDI - SF cutoff score ≥ 0.5),
maternal BMI (normal / underweight, overweight, obese), low birth weight (< 2500 g, ≥ 2500 g), whether the child takes a bottle to bed at
age 3 years (yes or no), and average hours of child television viewing per day at
age 3 years (< 2 h / d, ≥ 2 h / d).
Adjusted for the variables in
model 2 plus child's sex, birth weight and height, gestational
age,
maternal smoking during pregnancy,
maternal education,
maternal age, prepregnancy height and body mass index, breastfeeding,
maternal smoking at child's
age 4 years, number of siblings at child's
age 4 years, and child's consumption of sweetened beverages, sweets, and meat at
age 4 years.
Then, we examined whether
maternal problems in reciprocal social behavior directly or indirectly influenced infantile aggression at 18 months of
age by including
maternal PDS into the
model (see bottom of Figure 1).
As demonstrated in Table 2, children whose mothers reported chronic IPV were 80 % more likely to be obese at
age 5 years than those with no
maternal IPV in the
model 1 analysis adjusted for all covariates (OR = 1.80; 95 % confidence interval [CI], 1.24 - 2.61).
Univariate generalized linear
models were used to determine the estimated marginal means of the PedsQL scales and subscales adjusting for the child's
age, sex,
maternal education, and disadvantage index as covariates.
In these
models, estimates were adjusted for the child's
age, sex, and race - ethnicity; family ITNR; and
maternal education, depressive symptoms, and figure rating.
It was interesting to note that in our sample, only 25 % of the variance in child BMI at time 2 could be explained by the combined
model of T1 child BMI,
maternal BMI,
age and education, and child
age and gender.
Maternal age at delivery, ethnicity, smoking during pregnancy, parity, paternal diabetes status at follow - up, family social class, sex, offspring physical activity, and offspring smoking habits were not found to be confounders and had no effect on offspring risk of type 2 diabetes / pre-diabetes when entered in multiple logistic regression
models.
Logistic regression
models were used for controlling eight confounding variables such as
maternal age,
maternal education, employment status, parity,
maternal BMI, hypertension, diabetes and medically assisted conception.
Maternal reports of acceptance interacted with
age to predict adherence (β = −.24; p <.05), however, the F - value for the overall
model was marginally significant in this case (p =.08) so this result should be treated with caution.
The present study addressed these issues by using person - oriented (latent growth mixture) methods to
model heterogeneity in
maternal - reported internalizing symptoms from
age 2 to 11 years (N = 1,364).
The following variables were included in all 6 multivariate
models:
maternal race / ethnicity, education,
age, income, and nativity.
Note: 1
Maternal reports of partner's alcohol consumption; 2Univariable multinomial logistic regression
models; 3Multinomial logistic regression
models adjusted for
maternal age at delivery, parity, Social economic position,
maternal education,
maternal smoking during first trimester in pregnancy, housing tenure, income, and
maternal depressive symptoms at 32 weeks gestation; CL: childhood limited, AO: adolescent onset, EOP: early onset persistent, the Low conduct problems class was used as the reference group.
Maternal age was initially examined as a covariate, but it did not provide predictive value and was strongly correlated with SES (r =.60, p <.001), so it was dropped from the final
model for power and parsimony.
1
Maternal reports of partner's alcohol consumption;
Model 1 adjusted for
maternal age at delivery, parity, social economic position,
maternal education,
maternal smoking during first trimester in pregnancy, housing tenure, income, and
maternal depressive symptoms at 32 weeks gestation;
Model 2 further adjusted for
maternal alcohol use at 18 weeks gestation.
1
Maternal reports of partner's alcohol consumption; 2Univariable linear regression
models; 3
Models adjusted for
maternal age at delivery, parity, social economic position,
maternal education,
maternal smoking during first trimester in pregnancy, housing tenure, income, and
maternal depressive symptoms at 32 weeks gestation.
Longitudinal
models were applied to assess the relationships between
maternal pre-pregnancy BMI and affective problems from
age 5 through 17.
We then examined this
model with youth - reported antisocial behaviors (ASB) and
maternal depressive symptoms when the boys were older,
ages 10 to 15.
In the logistic regression
models, no infant,
maternal or family factors from the original Infant Sleep Study (conducted when the children were
aged 6 — 12 months) predicted the presence of sleep problems at the
age of 3 to 4 years.