Poor agreement between self-reported birth weight and birth weight from original records in adult women

Associations of maternal preterm birth with subsequent risk for type 2 diabetes in women from the women's health initiative

Preterm birth has been associated with insulin resistance and beta-cell dysfunction, a hallmark characteristic of type 2 diabetes. However, studies investigating the relationship between a personal history of being born preterm and type 2 diabetes are sparse. We sought to investigate the potential association between a personal history of being born preterm and risk for type 2 diabetes in a racially and ethnically diverse population. Baseline and incident data (>16 years of follow-up) from the Women's Health Initiative (n = 85,356) were used to examine the association between personal history of being born preterm (born 1910-1940s) and prevalent (baseline enrollment; cross-sectional) or incident (prospective cohort) cases of type 2 diabetes. Logistic and Cox proportional hazards regression models were used to estimate odds and hazards ratios. Being born preterm was significantly, positively associated with odds for prevalent type 2 diabetes at enrollment (adjOR = 1.79, 95% CI 1.43-2.24; P < 0.0001). Stratified regression models suggested the positive associations at baseline were consistent across race and ethnicity groups. However, being born preterm was not significantly associated with risk for incident type 2 diabetes. Regression models stratified by age at enrollment suggest the relationship between being born preterm and type 2 diabetes persists only among younger age groups. Preterm birth was associated with higher risk of type 2 diabetes but only in those diagnosed with type 2 diabetes prior to study enrollment, suggesting the association between preterm birth and type 2 diabetes may exist at earlier age of diagnosis but wane over time.

Parent-reported birth information: birth weight, birth length and gestational age. Validation study in the SENDO project

OBJECTIVE

To test the validity of parent-reported birth information obtained through an online, self-administered questionnaire.

METHOD

The SENDO project is a prospective and dynamic paediatric cohort of Spanish children aged 4 to 6 years old at recruitment. Objective data from medical birth records were compared to parent-reported data getting intra-class correlation coefficients (ICC) for quantitative variables and weighted Kappa Index for qualitative ones. Percentage of responders and of total agreement was also evaluated.

RESULTS

Parental response rate was over 99% for birth weight and gestational age and 76% for birth length. ICC for birth weight was 0.95 (95% confidence interval [95%CI]: 0.94-0.96) and 0.78 (95%CI: 0.73-0.83) for birth length, both showing very high correlations. The total agreement percentage for gestational age was 97%, and Kappa weighted index was 0.90 (95%CI: 0.89-0.90), showing a very high agreement as well.

CONCLUSIONS

We found high correlations and excellent agreement in parent-reported birth data 4 to 6 years after delivery. Our results show parent-reported birth data, especially birth weight, are valid for use in epidemiological research.

Validity of Self-Reported Birth Weight: Results from a Norwegian Twin Sample

The association between birth weight and later life outcomes is of considerable interest in life-course epidemiology. Research often relies on self-reported measures of birth weight, and its validity is consequently of importance. We assessed agreement between self-reported birth weight and official birth records for Norwegian twins born 1967–1974. The intraclass correlation between self-reported birth weight and register-based birth weight was 0.91 in our final sample of 363 twins. It could be expected that 95% of self-reported birth-weight values will deviate from official records within a maximum of +446 grams and a minimum of −478 grams — around a mean deviation of 16 grams. Self-reported birth weight had a sensitivity of 0.78–0.89 and a positive predictive value of 0.59–0.85, and an overall weighted kappa of 0.71. We further assessed agreement by conducting two linear regression models where we respectively regressed self-reported birth weight and register-based birth weight on adult body mass index, a known association. The two models were not significantly different; however, there were different levels of significance in parameter estimates that warrant some caution in using self-reported birth weight. Reliability of self-reported birth weight was also assessed, based on self-reports in another sample of twins born 1935–1960 who had reported their birth weight in two questionnaires 34 years apart. The intraclass correlation was 0.86, which indicates a high degree of reliability. In conclusion, self-reported birth weight, depending on context and age when birth weight was reported, can be cautiously used.

Validity of recalled v. recorded birth weight: a systematic review and meta-analysis

Low birth weight is associated with adverse health outcomes. If birth weight records are not available, studies may use recalled birth weight. It is unclear whether this is reliable. We performed a systematic review and meta-analysis of studies comparing recalled with recorded birth weights. We followed the Meta-Analyses of Observational Studies in Epidemiology (MOOSE) statement and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched MEDLINE, EMBASE and Cumulative Index to Nursing and Allied Health Literature (CINAHL) to May 2015. We included studies that reported recalled birth weight and recorded birth weight. We excluded studies investigating a clinical population. Two reviewers independently reviewed citations, extracted data, assessed risk of bias. Data were pooled in a random effects meta-analysis for correlation and mean difference. In total, 40 studies were eligible for qualitative synthesis (n=78,997 births from 78,196 parents). Agreement between recalled and recorded birth weight was high: pooled estimate of correlation in 23 samples from 19 studies (n=7406) was 0.90 [95% confidence interval (CI) 0.87–0.93]. The difference between recalled and recorded birth weight in 29 samples from 26 studies (n=29,293) was small [range −86–129 g; random effects estimate 1.4 g (95% CI −4.0–6.9 g)]. Studies were heterogeneous, with no evidence for an effect of time since birth, person reporting, recall bias, or birth order. In post-hoc subgroup analysis, recall was higher than recorded birth weight by 80 g (95% CI 57–103 g) in low and middle income countries. In conclusion, there is high agreement between recalled and recorded birth weight. If birth weight is recalled, it is suitable for use in epidemiological studies, at least in high income countries.

Relationships between misreported energy intake and pregnancy in the pregnancy, infection and nutrition study: new insights from a dynamic energy balance model

OBJECTIVE

Providing effective dietary counselling so that pregnancy weight gain remains within the 2009 Institute of Medicine (IOM) guidelines requires accurate maternal energy intake measures. Current practice is based on self-reported intake that has been demonstrated unreliable. This study applies an objective calculation of energy intake from a validated mathematical model to identify characteristics of individuals more likely to misreport during pregnancy.

METHODS

A validated maternal energy balance equation was used to calculate energy intake from gestational weight gain in 1,368 subjects. The difference between self-reported and model-predicted energy intake was tested for demographics, economic status, education level and maternal health status.

RESULTS

A weight gain of 15.2 kg resulted in model-predicted intake during pregnancy of 2,882.97 ±  135.71 kcal day-1, which differed from self-reported intake of 2,180.5 ± 856.0 kcal day-1. The achieved weight gain exceeded the IOM guidelines; however, the model predicted weight gain from self-reported energy intake was below IOM guidelines. Higher income (p = 0.004), education (p = 0.003), birth weight (p = 0.017), gestational diabetes (p = 0.008) and pre-existing diabetes (p < 0.001) were associated with under-reported energy intake. More children living at home (p = 0.001) were associated with more accurate self-reported intake.

CONCLUSIONS

When assessing self-reported energy intake in pregnancy studies, birth weight, gestational diabetes status, pre-existing diabetes, higher income and education predict higher under-reporting. Clinicians providing dietary treatment recommendations during pregnancy should be aware that individuals with pre-existing diabetes and gestational diabetes mellitus are more likely to misreport their intake. Additionally, the systems model approach can be applied early in intervention to objectively monitor dietary compliance to treatment recommendations.

Diversity and composition of the adult fecal microbiome associated with history of cesarean birth or appendectomy: Analysis of the American Gut Project

Background

Cesarean birth is associated with altered composition of the neonate's microbiota and with increased risk for obesity and other diseases later in life. The mechanisms of these associations, and whether cesarean birth is associated with an altered adult microbiota, are unknown.

Methods

In 1097 adult volunteers without diabetes, inflammatory bowel disease, or recent antibiotic use, fecal microbiome metrics were compared by history of cesarean birth (N = 92) or appendectomy (N = 115). Associations with potential confounders, microbiome alpha diversity, and individual microbial taxa were estimated by logistic regression. Permutation tests assessed differences in microbial composition (beta diversity) based on Jensen–Shannon divergence.

Findings

Cesarean birth history was associated with younger age; appendectomy with older age and higher body mass index. Neither was associated with fecal microbiome alpha diversity. Microbial composition at all taxonomic levels differed significantly with cesarean birth (P ≤ 0.008) but not with appendectomy (P ≥ 0.29). Relative abundance differed nominally for 17 taxa with cesarean birth and for 22 taxa with appendectomy, none of which was significant with adjustment for multiple comparisons.

Interpretation

Adults born by cesarean section appear to have a distinctly different composition of their fecal microbial population. Whether this distinction was acquired during birth, and whether it affects risk of disease during adulthood, are unknown.

Funding

Supported by the Intramural Research Program, National Cancer Institute, National Institutes of Health (Z01-CP-010214).

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Fecal microbiome differed in composition for adults who had been born by cesarean section versus vaginal delivery.

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No difference was found for adults with a history of appendectomy.

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Source of the cesarean-associated microbiome distinction, and possible effects on disease during adulthood, is unknown.

Birth weight and adult cancer incidence: large prospective study and meta-analysis

BACKGROUND

Most evidence about associations between birth weight and adult cancer risk comes from studies linking birth records to cancer registration data, where information on known risk factors for cancer is generally lacking. Here, we report on associations between birth weight and cause-specific cancer risk in a large cohort of UK women, and investigate how observed associations are affected by other factors.

METHODS

A total of 453 023 women, born in the 1930s and 1940s, reported their birth weight, maternal smoking, parental heights, age at menarche, adult height, adult smoking, and many other personal characteristics. They were followed for incident cancer. Using Cox regression, relative risks by birth weight were estimated for cancers with more than 1500 incident cases, adjusting for 17 potential confounding factors, individually and simultaneously.

RESULTS

Birth weight reported in adulthood was strongly correlated with that recorded at birth (correlation coefficient = 0.78, P < 0.0001). Reported birth weight was associated with most of the potential confounding factors examined, the strongest association being with adult height. After 9.2 years follow-up per woman, 39 060 incident cancers were registered (4414 colorectal, 3175 lung, 1795 malignant melanoma, 14 542 breast, 2623 endometrial, 2009 ovarian, 1565 non-Hodgkin lymphoma, and 8937 other cancers). Associations with birth weight were null or weak and reduced after adjustment by adult height (P[trend] > 0.01 for every cancer, after adjustment). In contrast, adult height was strongly related to the risk of every cancer except lung cancer, after adjusting for birth weight and other factors (P[trend] < 0.0001 for most cancers). For lung cancer, adjusting for smoking reduced the association with birth weight. Meta-analyses were dominated by our findings.

CONCLUSION

Birth weight and adult height are correlated and likely to be markers of some aspect of growth that affects cancer risk in adulthood. However, birth weight adds little, if any, additional information to adult height as a predictor of cancer incidence in women.

Impact of size at birth and prematurity on adult anthropometry in 4744 middle-aged Danes - The Inter99 study

Low birth weight is related to increased risk of developing cardiovascular disease and type 2 diabetes in adult life. Since obesity is closely associated with type 2 diabetes and cardiovascular disease, the relationship between size at birth and adult anthropometry is of interest as a mediator of the relationship between birth weight and metabolic diseases. The aim of this study was, therefore, to examine the effect of size at birth and prematurity on measures of adult anthropometry taking adult socio-economic status and lifestyle variables into account. Midwife records with information on mother's age and parity as well as weight, length and maturity at birth were traced in 4744 Danes born between 1939 and 1970. Measures of adult anthropometry (weight, height, body mass index (BMI), waist circumference, hip circumference and waist/hip ratio) had previously been recorded together with information on socio-economic factors, lifestyle and parental diabetes status. Mother's age, parity and diabetes status were associated with offspring birth weight. Size at birth was positively associated with adult height and weight, but only weakly associated with BMI and not associated with waist/hip ratio when adjusted for socio-economic and lifestyle factors. Infants born preterm were less growth restricted at birth and grew to be taller and heavier compared with term infants born small for gestational age. Altogether, this study does not find evidence that obesity or a central fat distribution is mediating the relationship between low birth weight and risk of cardiovascular disease or type 2 diabetes in later life.

Agreement between self-reported birth weight and birth certificate weights

Birth weight is emerging as a potentially important risk factor for several chronic diseases with adult onset, including breast cancer. Because participant recall is frequently used to gather data on early life exposures, it is essential that the accuracy of recall be assessed and validated. Self-reported birth weights and birth certificate weights were compared in women aged 35-51 years from the Western New York Exposures and Breast Cancer (WEB) Study, a population-based case-control study. A total of 180 participants had both birth certificate and interview data on birth weight. Participants reported birth weight to one of six categories (<5, 5-5.5, 5.6-7, 7.1-8.5, 8.6-10 and >10 lbs). The Spearman correlation for self-reported and birth certificate weights was 0.67. Sixty percent of participants reported weights with exact agreement with birth certificate; unweighted and weighted kappas (κ) were 0.39 and 0.68, respectively. Spearman correlations were similar for cases (0.67) and controls (0.68). Controls exhibited a significantly higher unweighted κ (0.51) than cases (0.27; P = 0.03), but weighted κ were not statistically different [controls, 0.73; cases, 0.64 (P = 0.32)]. Demographic and anthropometric characteristics were not different between participants who underreported, overreported, or correctly reported their birth weight for either cases or controls. Overall, the level of agreement for report of birth weight and actual birth weight was fair to moderate.

Ethnic differences in the relationship between birth weight and type 2 diabetes mellitus in postmenopausal women

AIM

The objective of this study is to examine the relationship between self-reported birth weight and the adult occurrence of type 2 diabetes mellitus in a large multi-ethnic population of women.

METHODS

Baseline data from the Women's Health Initiative Observational Study [n=75,993] was used to examine the association between participant birth weight category and prevalent type 2 diabetes mellitus. Models were adjusted for age, ethnicity, body mass index and other pertinent risk factors. Sub-analyses were performed stratifying by ethnicity.

RESULTS

There was a strong inverse association between birth weight and type 2 diabetes mellitus with a birth weight of <6 pounds (lbs) (OR: 1.16, 95% CI: 1.01, 1.33) significantly associated with an increased risk of type 2 diabetes mellitus and a birth weight of ≥10 lbs (OR: 0.72, 95% CI: 0.57, 0.92) associated with a decreased risk of type 2 diabetes mellitus compared to women who reported their birth weight between 7 and 8 lbs 15 ounces (oz). Stratifying by ethnicity, the inverse association between birth weight and type 2 diabetes mellitus was only apparent in White women, but not Black, Hispanic or Asian women.

CONCLUSION

Lower birth weight was associated with increased T2D risk in American White and Black post-menopausal women.

Low birthweight and risk of albuminuria in living kidney donors

Low birthweight is linked to hypertension, chronic kidney disease and even end-stage renal disease. We hypothesized that living kidney donors born with lower birthweight may be at increased risk of hypertension, albuminuria, or reduced GFR beyond what is typical following uninephrectomy. Two hundred fifty-seven living kidney donors who donated at the University of Minnesota between 1967 and 2005 underwent iohexol GFR and urinary albumin excretion measurements. Predictors of iohexol GFR <60 mL/min/1.73 m(2), albuminuria, and hypertension were examined using logistic regression. Predictors examined include age at GFR measurement, time since donation, BMI, gender, serum creatinine level (at donation and GFR measurement), systolic and diastolic blood pressure, race, and birthweight. The latter was obtained through self-report and verified through birth certificates and family members. Older age, higher BMI, and time from donation were associated with reduced GFR. Older age and higher BMI were also associated with hypertension. Birthweight was not associated with GFR <60 mL/min/1.73 m(2): OR=0.70, 95% CI (0.28, 1.74), p = 0.45 or hypertension: OR=0.92, 95% CI (0.46, 1.84), p = 0.82 but was associated with albuminuria: OR=0.37, 95% CI (0.15, 0.92), p = 0.03. These data further strengthen the link between low birthweight and potential adverse renal outcomes.

Self-reported weight at birth predicts measures of femoral size but not volumetric BMD in eldery men: MrOS

The mechanism whereby poor intrauterine growth increases risk of adult hip fracture is unclear. We report the association between birth weight and proximal femoral geometry and density in community-dwelling elderly men. We used self-reported birth weight, measured adult height and weight and proximal femoral quantitative computed tomography (QCT) measurements of femoral neck axis length, cross-sectional area, and volumetric BMD (vBMD) among the participants in the Osteoporotic Fractures in Men (MrOS), a cohort study of community-dwelling US men aged 65 and older. We compared men with birth weight <7 pounds (lower birth weight [LBW]; n = 501) and ≥ 9 pounds (higher birth weight [HBW]; n = 262) with those weighing 7-8.9 pounds (medium birth weight [MBW], referent group; n = 1068) using linear regression adjusting for current age, height, and BMI. The mean age of the 1831 men who had both birth weight and QCT measurements was 73 years (SD 5.9). Compared with the referent MBW, HBW men had concordantly longer femoral neck (+0.16 SD; p = .028) and cross-sectional area (+0.24 SD, p = .001). LBW men had a smaller cross-sectional (-0.26 SD, p < .001) but longer femoral neck for their height (+0.11 SD, p = .05). Neither cortical nor trabecular vBMD at the femoral neck was associated with birth weight. These findings support the hypothesis that the skeletal envelope, but not density, is set, in part, at birth. Further research exploring the association between early developmental factors and lifetime fracture risk is needed and may inform primary preventative strategies for fracture prevention.

Lifetime body size and reproductive factors: comparisons of data recorded prospectively with self reports in middle age

Background

Data on lifetime exposures are often self-reported in epidemiologic studies, sometimes many years after the relevant age. Validity of self-reported data is usually inferred from their agreement with measured values, but few studies directly quantify the likely effects of reporting errors in body size and reproductive history variables on estimates of disease-exposure associations.

Methods

The MRC National Survey of Health and Development (NSHD) and the Million Women Study (MWS) are UK population-based prospective cohorts. The NSHD recruited participants at birth in 1946 and has followed them at regular intervals since then, whereas the MWS recruited women in middle age. For 541 women who were participants in both studies, we used statistical measures of association and agreement to compare self-reported MWS data on body size throughout life and reproductive history, obtained in middle age, to NSHD data measured or reported close to the relevant ages. Likely attenuation of estimates of linear disease-exposure associations due to the combined effects of random and systematic errors was quantified using regression dilution ratios (RDRs).

Results

Data from the two studies were very strongly correlated for current height, weight and body mass index, and age at menopause (Pearson r = 0.91-0.95), strongly correlated for birth weight, parental heights, current waist and hip circumferences and waist-to-height ratio (r = 0.67-0.80), and moderately correlated for age at menarche and waist-to-hip ratio (r = 0.52-0.57). Self-reported categorical body size and clothes size data for various ages were moderately to strongly associated with anthropometry collected at the relevant times (Spearman correlations 0.51-0.79). Overall agreement between the studies was also good for most quantitative variables, although all exhibited both random and systematic reporting error. RDRs ranged from 0.66 to 0.86 for most variables (slight to moderate attenuation), except weight and body mass index (1.02 and 1.04, respectively; little or no attenuation), and age at menarche, birth weight and waist-to-hip ratio (0.44, 0.59 and 0.50, respectively; substantial attenuation).

Conclusions

This study provides some evidence that self-reported data on certain anthropometric and reproductive factors may be adequate for describing disease-exposure associations in large epidemiological studies, provided that the effects of reporting errors are quantified and the results are interpreted with caution.

Depression in Swedish women: relationship to factors at birth

Depression is a common and serious disorder that may have developmental origins. Birth-related factors have been related to childhood and adult occurrence of somatic as well as psychiatric disorders, but studies on the relationship between birth-related factors and depression are few and show mixed results. In addition, varying methods have been used to assess depression. Standardized clinical criteria to diagnose depression, combined with birth data collected from midwife records have not been used in most studies. Participants in the Prospective Population Study of Women in Sweden (803 women), born 1914, 1918, 1922 and 1930, provide information on birth factors and depression. Women participated from 1968 at mid-life ages of 38-60 years, to 2000, when they were age 78-92 years. Original birth records containing birth weight, length, head circumference, and gestational time, as well as social factors were obtained. Lifetime depression was diagnosed via multiple information sources. Symptoms were assessed using the Comprehensive Psychopathological Rating Scale and diagnoses were based on DSM-III-R criteria. Over their lifetime, 44.6% of women in this sample experienced depression. Birth weights ≤ 3500 g [odds ratio (OR), age-adjusted = 1.72; 95% CI 1.29-2.28, P < 0.001] and shorter gestational time (OR, age-adjusted = 1.13; 95% CI 1.04-1.24, P = 0.005) were independently associated with a higher odds of lifetime depression in a logistic regression model adjusted for age. Lower than median birth weights and shorter gestational time were related to lifetime depression in women. Both neurodevelopmental and environmental contributions to lifetime depression may be considered.

Association between birth weight and visceral fat in adults

BACKGROUND

Several studies reported inverse associations between birth weight and central adiposity in adults. However, few studies investigated the contributions of different abdominal fat compartments.

OBJECTIVE

We examined associations between birth weight and adult visceral and subcutaneous abdominal fat in the population-based Fenland study.

DESIGN

A total of 1092 adults (437 men and 655 women) aged 30-55 y had available data on reported birth weight, standard anthropometric measures, and visceral and subcutaneous abdominal fat estimated by ultrasound. In a subgroup (n = 766), dual-energy X-ray absorptiometry assessment of total abdominal fat was performed. Linear regression models were used to analyze relations between birth weight and the various fat variables adjusted for sex, age, education, smoking, and body mass index (BMI).

RESULTS

After adjustment for adult BMI, there was an inverse association between birth weight and total abdominal fat [B (partial regression coefficient expressed as SD/1-kg change in birth weight) = -0.09, P = 0.002] and visceral fat (B = -0.07, P = 0.01) but not between birth weight and subcutaneous abdominal fat (B = -0.01, P = 0.3). Tests for interaction showed that adult BMI modified the association between birth weight and visceral fat (P for interaction = 0.01). In stratified analysis, the association between birth weight and visceral fat was apparent only in individuals with the highest BMI tertile (B = -0.08, P = 0.04).

CONCLUSIONS

The inverse association between birth weight and adult abdominal fat appeared to be specific to visceral fat. However, associations with birth weight were apparent only after adjustment for adult BMI. Therefore, we suggest that rapid postnatal weight gain, rather than birth weight alone, leads to increased visceral fat.

Validity of self-reported birth weight by adult women: sociodemographic influences and implications for life-course studies

Life-course epidemiologic studies frequently obtain data on perinatal and childhood factors through adult self-report. Data from a prospective US birth cohort of 262 women, born between 1959 and 1963 (average age at adult follow-up, 41.8 years), were used to assess the validity of self-reported birth weight category by sociodemographic characteristics. The effect of reporting error on the associations of birth weight with childhood and adult body mass index was evaluated by comparing the estimates of associations from linear regression analyses. The level of agreement between the birth weight category reported by 85% of the participants and the birth weight recorded at the time of birth was moderate to good (sensitivity = 73%, weighted kappa = 0.67). The validity varied by birth weight category (sensitivity range = 58%-81% for the lowest and highest birth weight category, respectively) and was highest for participants who were white, of lower childhood family income, and born to older mothers. Despite this moderate to good validity, the associations of birth weight with childhood and adult body mass index were attenuated and no longer statistically significant when self-reported birth weight was used. In conclusion, birth weight reported in middle adult life is measured with error, limiting its utility for detecting modest associations with health in later life periods.

The role of birth cohorts in studies of adult health: the New York women's birth cohort

Epidemiological studies investigating associations between early life factors and adult health are often limited to studying exposures that can be reliably recalled in adulthood or obtained from existing medical records. There are few US studies with detailed data on the pre- and postnatal environment whose study populations are now in adulthood; one exception is the Collaborative Perinatal Project (CPP). We contacted former female participants of the New York site of the CPP who were born from 1959 to 1963 and were prospectively followed for 7 years to examine whether the pre- and postnatal environment is associated with adult health in women 40 years after birth. The New York CPP cohort is particularly diverse; at enrolment, the race/ethnicity distribution of mothers was approximately 30% White, 40% Black and 30% Puerto Rican. Of the 841 eligible women, we successfully traced 375 women (45%) and enrolled 262 women (70% of those traced). Baseline data were available for all eligible women, and we compared those who participated with the remaining cohort (n = 579). Higher family socio-economic status at age 7, availability of maternal social security number, and White race/ethnicity were statistically significantly associated with a higher probability of tracing. Of those traced, race/ethnicity was associated with participation, with Blacks and Puerto Ricans less likely to participate than Whites (OR = 0.5, 95% CI 0.3, 0.8, and OR = 0.5, 95% CI 0.3, 1.0, respectively). In addition, higher weight at 7 years was associated with lower participation (OR = 0.95, 95% CI 0.92, 0.99), but this association was observed only among the non-White participants. None of the other maternal characteristics, infant or early childhood growth measures was associated with participation or with tracing, either overall or within each racial/ethnic subgroup. Daughters' recall of early life factors such as pre-eclampsia (sensitivity = 24%) and birthweight were generally poor, with the latter varying by category of birthweight with the highest sensitivity for the largest babies (81%) and the lowest sensitivity for the smallest babies (54%). These data reinforce the need to rejuvenate existing birth cohorts with prospective data for life course studies of adult health. Understanding the factors that are associated with tracing and participation in these existing cohorts will help in interpreting the validity and generalisability of the findings from these invaluable cohorts.

Weight and length at birth and their relationship to diabetes incidence and all-cause mortality--a 32-year follow-up of the population study of women in Gothenburg, Sweden

OBJECTIVE

The purpose of the study was to explore the relationship of weight and length at birth to diabetes in adult life and to all-cause mortality. Special attention was taken to potential confounding factors as age, family history, education, socio-economic group, physical inactivity, smoking, blood pressure, serum lipids and obesity.

RESEARCH DESIGN AND METHODS

A longitudinal population study consisting of a representative sample of 1381 women aged 38-54 started in Gothenburg, Sweden, in 1968-1969 monitoring for diabetes mellitus and overall mortality over 32 years. Original delivery records were retrieved for 61.2% of the women. Death certificates were obtained for 99.3% the women who died during the 32-year follow-up period.

RESULTS

We observed an inverse statistically significant relationship between birth weight and 32-year diabetes incidence independent of age, the highest incidence 16.3% in the lowest quartile of birth weight compared to 9.2% in the highest quartile. The relationship remained when controlling for the following covariates: education, socio-economic group, physical activity, smoking, systolic blood pressure, adult body mass index (BMI), waist-hip ratio, serum triglycerides and cholesterol. When overweight women (BMI> or =25) were excluded from the statistical analyses birth weight was even stronger related to the incidence of diabetes, 12.8% in lowest quartile and 5.7% in the highest quartile of birth weight independent of birth length, education, socio-economic group, physical activity, smoking, systolic blood pressure, body mass index, waist-hip ratio, blood glucose, serum triglycerides and cholesterol. Length at birth was a predictor for diabetes independent of age plus adult body mass index (BMI) and smoking but not independent of age only. No significant associations were observed between birth factors as birth weight and birth length and overall mortality during the 32-year of follow-up.

CONCLUSIONS

A low birth weight seems to be a risk factor for diabetes in adult women independent of age and most of the established risk factors for diabetes.

Birth weight in relation to endometrial and breast cancer risks in Swedish women

An examination of birth weight in a Swedish cohort study of 38,566 women showed no significant association between birth weight and endometrial cancer, but supported a protective role for low birth weight for premenopausal breast cancer.

Reports of birthweight by adolescents and their mothers: comparing accuracy and identifying correlates

Birthweight is associated with health outcomes throughout the lifespan. Official birthweight records are not always available, and researchers must rely on self-reports for birthweight information. This study evaluates the accuracy of adolescent self-reports of birthweight, using medical records as a standard, and compares it with maternal reports. It also examines potential correlates of accuracy. Respondents are 17-year-old adolescents and their mothers, who participated in a follow-up study of randomly selected samples from newborn discharge lists (1983-85) of two major hospitals in south-east Michigan. Nearly one-quarter of the adolescents stated that they did not know their own birthweight, with males twice as likely as females to respond 'don't know'. In addition, self-reports of birthweight among the remaining adolescents were inaccurate, and accuracy was inversely related to birthweight. While maternal reports of offspring's birthweight are highly accurate across diverse subgroups of the population, adolescent self-reports of birthweight are unlikely to be useful in medical research.

Maternal upward socioeconomic mobility and black-white disparities in infant birthweight

OBJECTIVES

We estimate the extent to which upward socioeconomic mobility limits the probability that Black and White women who spent their childhoods in or near poverty will give birth to a low-birthweight baby.

METHODS

Data from the National Longitudinal Survey of Youth 1979 and the 1970 US Census were used to complete a series of logistic regression models. We restricted multivariate analyses to female survey respondents who, at 14 years of age, were living in households in which the income-to-needs ratio did not exceed 200% of poverty.

RESULTS

For White women, the probability of giving birth to a low-birthweight baby decreases by 48% for every 1 unit increase in the natural logarithm of adult family income, once the effects of all other covariates are taken into account. For Black women, the relation between adult family income and the probability of low birthweight is also negative; however, this association fails to reach statistical significance.

CONCLUSIONS

Upward socioeconomic mobility contributes to improved birth outcomes among infants born to White women who were poor as children, but the same does not hold true for their Black counterparts.

Prenatal and perinatal correlates of adult mammographic breast density

BACKGROUND

Adult mammographic percent density is one of the strongest known risk factors for breast cancer. In utero exposure to high levels of endogenous estrogens (or other pregnancy hormones) has been hypothesized to increase breast cancer risk in later life. We examined the hypothesis that those factors associated with higher levels of estrogen during pregnancy or shortly after birth are associated with higher mammographic breast density in adulthood.

METHODS

We analyzed data on 1,893 women from 360 families in the Minnesota Breast Cancer Family Study who had screening mammograms, risk factor data, over age 40, and no history of breast cancer. Prenatal and perinatal risk factor data were ascertained using a mailed questionnaire. Mammographic percent density and dense area were estimated from the mediolateral oblique view using Cumulus, a computer-assisted thresholding program. Linear mixed effects models incorporating familial correlation were used to assess the association of risk factors with percent density, adjusting for age, weight, and other breast cancer risk factors, all at time of mammography.

RESULTS

The mean age at mammography was 60.4 years (range, 40-91 years), and 76% were postmenopausal. Among postmenopausal women, there was a positive association of birthweight with percent density (P trend <0.01), with an adjusted mean percent density of 17.1% for <2.95 kg versus 21.0% for > or = 3.75 kg. There were suggestive positive associations with gestational age (mean percent density of 16.7% for preterm birth, 20.2% for term birth, and 23.0% for late birth; P trend = 0.07), maternal eclampsia/preeclampsia (mean percent density of 19.9% for no and 14.6% for yes; P = 0.16), and being breast-fed as an infant (mean percent density of 18.2% for never and 20.0% for ever; P = 0.08). There was no association of percent density with maternal age, birth order, maternal use of alcohol or cigarettes, or neonatal jaundice. Except for being breast-fed, these associations showed similar but attenuated trends among premenopausal women, although none were statistically significant. The results for dense area paralleled the percent density results. The associations of gestational age and being breast-fed as an infant with percent density attenuated when included in the same model as birthweight.

CONCLUSIONS

Birthweight was positively associated with mammographic breast density and dense area among postmenopausal women and more weakly among premenopausal women, suggesting that it may be a marker of this early life exposure. These results offer some support to the hypothesis that pregnancy estrogens or other pregnancy changes may play a role in breast cancer etiology, and suggest that these factors may act in part through long-term effects on breast density.

Medical records vs. interview responses: a comparative analysis of selected variables for linked birth defect cases

BACKGROUND

Data pertaining to birth defects are subject to certain limitations depending on the collection method. This study compares the agreement of data from medical records and maternal interviews.

METHODS

The medical records and maternal interviews were linked for 1017 deliveries. Prevalence, concordance and kappa coefficients were calculated for maternal gestational and non-gestational diabetes, insulin use, seizures/epilepsy, Hispanic ethnicity, and infant/fetus sex.

RESULTS

The prevalence of non-gestational diabetes was 4.3% in the medical records and 3.4% in the maternal interviews, with 98.1% agreement. The prevalence of gestational diabetes was 7.9% in medical records and 9.2% in maternal interviews, with 94.3% agreement. Similar prevalences and high levels of agreement were observed between the two systems for infant/fetus sex and mother's Hispanic ethnicity. Although high concordance was observed for seizures/epilepsy, kappa value was moderate.

CONCLUSIONS

The availability of two distinct sources of data provides an exceptional opportunity to compare and validate both data sources. We found that the data for certain variables from maternal interviews strongly agreed with information from medical records. However, the extent of that agreement depended on the type of variable measured. Our results suggest that for some variables such as demographic variables, researchers can use either of the two data sources.

The relation between birth weight and intima-media thickness in middle-aged adults

BACKGROUND

Birth weight has been found to be inversely associated with the risk of coronary heart disease and stroke, although the mechanisms for this association remain unclear. Here, we investigate the relation between reported birth weight and atherosclerosis in middle age.

METHODS

We included the 9817 participants (age 44-65) in the Atherosclerosis Risk in Communities (ARIC) study who were neither a twin nor born prematurely. Carotid atherosclerosis was assessed as intima-media thickness measured by B-mode ultrasound. We studied the association with recalled exact birth weight, and for those unable to recall exact birth weight, with recalled birth weight category.

RESULTS

Mean intima-media thickness (+/- standard deviation) was 0.73 +/- 0.17 mm. Mean birth weight for the 4635 participants recalling exact birth weight was 3.49 +/- 0.71 kg. A further 4946 participants recalled birth weight category, with 4730 (96%) reporting "medium" birth weight. In univariate analysis, birth weight and intima-media thickness were positively related. However, adjustment for confounding factors reduced the association to only a 0.004 mm higher intima-media thickness (95% CI = - 0.003 to 0.011) mm per 1 kg of birth weight. The same pattern of univariate positive relationship and attenuation with adjustment was seen for birth weight category and intima-media thickness. There was no evidence of interaction between adult body mass index (BMI) and birth weight, or of interaction between category of adult BMI and birth weight category. An inverse relation between birth weight category and intima-media thickness was seen only for those in the lowest category of adult BMI (BMI <25 kg/m).

CONCLUSIONS

We found no evidence of a clinically significant relation between birth weight and carotid atherosclerosis.

Birth weight and cognitive ability in childhood: a systematic review

Individual differences in cognitive ability may in part have prenatal origins. In high-risk (low birth weight/premature) babies, birth weight correlates positively with cognitive test scores in childhood, but it is unclear whether this holds for those with birth weights in the normal range. The authors systematically reviewed literature on the relationship between normal birth weight (more than 2,500 g) and childhood intelligence in term (37-42-week gestation) deliveries. Six studies met the inclusion criteria, and the authors present a comprehensive narrative review of these studies. There was a small, consistent, positive association between birth weight and childhood cognitive ability, even when corrected for confounders. Parental social class accounted for a larger proportion of the variance than birth weight, and these 2 variables were largely independent.

Birthweight, parental age, birth order and breast cancer risk in African-American and white women: a population-based case-control study

Introduction

Much recent work has focused on hypotheses that very early life exposures influence adult cancer risk. For breast cancer it has been hypothesized that high in utero estrogen exposure may increase risk.

Methods

We used data from the Carolina Breast Cancer Study, a population-based case–control study of incident breast cancer in North Carolina, to examine associations for three possible surrogates of high prenatal estrogen exposure: weight at birth, maternal age, and birth order. We also examined paternal age. Birthweight analyses were conducted for white and African-American women born in North Carolina on or after 1949 (196 cases, 167 controls). Maternal age was analyzed for US born participants younger than 49 years of age (280 cases, 236 controls).

Results

There was a weak inverse association between birthweight in the highest tertile and breast cancer overall (odds ratio [OR] 0.7, 95% confidence interval [CI] 0.4–1.2), although associations differed by race (OR 0.5, 95% CI 0.2–1.0, and OR 1.0, 95% CI 0.5–2.1 for African-American and white women, respectively). For maternal age there was an approximately threefold increase in risk in women whose mothers were older than 22 years of age, relative to 19–22 years of age, when the women were born. After adjustment for maternal age, older paternal age increased risk in the oldest and youngest age categories (relative to 23–27 years of age at the woman's birth: OR 1.6, 95% CI 0.8–3.1 for age 15–22 years; OR 1.2, 95% CI 0.7–2.2 for age 28–34 years; and OR 1.5, 95% CI 0.7–3.2 for age 35–56 years). There was no association with older paternal age for white women alone. After adjustment for maternal age (265 cases, 224 controls), a birth order of fifth or higher relative to first had an inverse association with breast cancer for women younger than 49 years old (OR 0.6, 95% CI 0.3–1.3).

Conclusion

Although the CIs are wide, these results lend support to the possibility that the prenatal period is important for subsequent breast cancer risk, but they do not support the estrogen hypothesis as a unifying theory for the influence of this period.

Relationship between gestational diabetes mellitus and low maternal birth weight

OBJECTIVE

To study the relationship between low birth weight and the presence of gestational diabetes mellitus (GDM) or peripheral insulin resistance during pregnancy.

RESEARCH DESIGN AND METHODS

We studied the relationship between peripheral insulin sensitivity (calculated by Matsuda and DeFronzo's oral glucose tolerance test (OGTT)-derived insulin sensitivity index [ISI(OGTT)]) or GDM prevalence and birth weight in 604 pregnant women, classified as normally glucose tolerant (n = 462) or affected with GDM (n = 142) after a 100-g 3-h oral glucose tolerance test. We then categorized these subjects into two groups: individuals with birth weight in the <10th percentile (<2,600 g; n = 68) and individuals with birth weight in the >10th percentile (n = 536).

RESULTS

GDM prevalence was higher in the group in the lowest birth weight decile (<2,600 g; 24/68; 35%) than in the group with normal/high birth weight (118/536; 22%; chi(2) = 5.917; P = 0.01). Relative risk for GDM adjusted for age, parity, family history of diabetes, and prepregnancy body weight was about twofold in the group with low birth weight (odds ratio = 1.89 [95% CI 1.088-3.285; P = 0.023]), and the prevalence of low birth weight was about threefold higher in the first ISI(OGTT) decile. In 450 women whose newborn's weight was known, the delivery of macrosomic babies was associated with a twofold higher relative risk for GDM in women who themselves had low birth weight. In the latter, the relationships between their newborn's weight and either maternal glucose tolerance (positive) or ISI(OGTT) (negative) were amplified.

CONCLUSIONS

Low maternal birth weight was associated with a twofold higher risk for GDM, independent of major confounders. Such a risk was highest in women with low birth weight who delivered macrosomic babies, and in the group with low birth weight, the relationship between maternal glucose tolerance or insulin resistance and offspring's neonatal weight was much more evident.

Impact of low birth weight on attention-deficit hyperactivity disorder

The objective of the study was to evaluate an association between low birth weight (LBW) and attention-deficit hyperactivity disorder (ADHD) attending to potential family-genetic and environmental confounders. We examined 252 ADHD cases (boys and girls) and 231 non-ADHD controls and their parents. All subjects were extensively assessed with structured diagnostic interviews, cognitive assessments, and structured interviews of prenatal, infancy, and delivery complications. ADHD cases were three times more likely to have been born LBW than were non-ADHD controls, after attending to potential confounders such as prenatal exposure to alcohol and cigarettes, parental ADHD, social class, and comorbid disruptive behavior disorders in parents and offspring. If this association was causal, 13.8% of all ADHD cases could be attributed to LBW. These results converge with prior studies documenting similar associations and indicate that LBW is an independent risk factor for ADHD. Children with LBW, however, make up a relatively small proportion of children with ADHD.

Blood pressure and hypertension in middle-aged women in relation to weight and length at birth: a follow-up study

OBJECTIVES

To examine the relationship between indicators at birth and adult blood pressure and risk for developing hypertension at two age levels.

DESIGN

Original midwife records of 438 women born at term participating in a prospective population study in Göteborg, Sweden with blood pressure and hypertension assessment at both 50 and 60 years of age.

RESULTS

Systolic blood pressure at both age levels showed a U-shaped relationship to weight and length at birth. Hypertension prevalence at 60 years was significantly and inversely related to both weight and length at birth, but not at 50 years. Significantly higher risk for hypertension was found in the lowest birth weight quintile [odds ratio (OR) = 2.0, 95% confidence interval (CI) 1.1-3.8] and lowest birth length tertile (OR = 1.8, 95% CI 1.1-3.0), in relation to the middle quintile/tertile, with or without adjustment for adult body size (as body mass index), at 60 years but not at 50 years. At 50 years, hypertension risk decreased by 3% (95% CI 0.92-1.01) for every 100 g increase in birth weight and 6% (95% CI 0.83-1.05) per cm birth length. At age 60 years, hypertension risk decreased by 4% (95% CI 0.92-0.99) per 100 g birth weight and 10% (95% CI 0.81-0.99) per cm length.

CONCLUSIONS

Size at birth was a predictor of hypertension risk in women at 60 years but not 50 years. This study supports the hypothesis that poor fetal growth, as measured by low weight or length at birth, may contribute to the development of hypertension in later life and that this relationship became stronger with age.