Multi-risk infants: predicting attachment security from sociodemographic, psychosocial, and health risk among African-American preterm infants

BACKGROUND

Ecological and transactional theories link child outcomes to accumulated risk. This study hypothesized that cumulative risk was negatively related to attachment, and that maternal sensitivity mediated linkages between risk and attachment.

METHODS

One hundred and twelve high-risk African-American premature infant-mother dyads participated. Psychosocial (maternal depression, stress and self-efficacy) and sociodemographic risk (poverty, maternal education, marital status) were maternal self-report (0-4 months). Infant health risk was obtained from hospital charts. Infant-mother attachment (12 months) and maternal sensitivity (4 months) were assessed with Q-sort measures.

FINDINGS

Psychosocial and sociodemographic risk, but not infant health risk, negatively related to attachment. Both were mediated by maternal sensitivity.

CONCLUSIONS

The impact of risk domains on attachment security was mediated by maternal sensitivity. Results emphasize the need for early intervention programs targeting premature infants to identify and address environmental and personal factors that place parenting at risk.

Cumulative risk exposure and mental health symptoms among maltreated youth placed in out-of-home care

OBJECTIVE

Maltreated children placed in out-of-home care are at high risk for exhibiting symptoms of psychopathology by virtue of their exposure to numerous risk factors. Research examining cumulative risk has consistently found that the accumulation of risk factors increases the likelihood of mental health problems. The goal of the current study was to elucidate the relation between cumulative risk and mental health symptomatology.

METHODS

The study consisted of a sample of 252 maltreated youths (aged 9-11) placed in out-of-home care.

RESULTS

Analyses confirmed the high-risk nature of this sample and identified seven salient risk variables. The cumulative risk index comprised of these seven indicators was a strong predictor of mental health symptoms, differentiating between children who scored in the clinical range with regard to mental health symptoms and those who did not. Finally, the data supported a linear model in which each incremental increase in cumulative risk was accompanied by an increase in mental health problems.

CONCLUSION

This is the first known study to examine cumulative risk within a sample of youths in out-of-home care.

Calculation of risk of colorectal and endometrial cancer among patients with Lynch syndrome

BACKGROUND & AIMS

Lynch syndrome is the most common hereditary colorectal cancer (CRC) syndrome. Some previous estimates of lifetime risk for CRC and endometrial cancer (EC) did not control for ascertainment and were susceptible to bias toward overestimated risk.

METHODS

We studied 147 families with mismatch repair gene mutations (55 MLH1, 81 MSH2, and 11 MSH6) identified at 2 US cancer genetics clinics. Age-specific cumulative risks (penetrance) and hazard ratio (HR) estimates of CRC and EC risks were calculated and compared with the general population using modified segregation analysis. The likelihood for each pedigree was conditioned on the proband and first-degree relatives affected with CRC to reduce ascertainment bias and overestimation of penetrance.

RESULTS

We analyzed 628 cases of CRC, diagnosed at the median ages of 42 and 47 years for men and women, respectively. The cumulative risk of CRC was 66.08% (95% confidence interval [CI], 59.47%-76.17%) for men and 42.71% (95% CI, 36.57%-52.83%) for women, with overall HRs of 148.4 and 51.1, respectively. CRC risk was highest for males with mutations in MLH1. There were 155 cases of EC, diagnosed at a median age of 47.5 years. The cumulative risk of EC was 39.39% (95% CI, 30.78%-46.94%) with an overall HR of 39.0 (95% CI, 30.4-50.2). For women, the cumulative risk of CRC or EC was 73.42% (95% CI, 63.76%-80.54%).

CONCLUSIONS

Lifetime risks of CRC and EC in mismatch repair gene mutation carriers are high even after adjusting for ascertainment. These estimates are valuable for patients and providers; specialized cancer surveillance is necessary.

The relations among cumulative risk, parenting, and behavior problems during early childhood

BACKGROUND

This study examined relations among cumulative risk, nurturant and involved parenting, and behavior problems across early childhood.

METHODS

Cumulative risk, parenting, and behavior problems were measured in a sample of low-income toddlers participating in a family-centered program to prevent conduct problems.

RESULTS

Path analysis was utilized to examine longitudinal relations among these constructs, with results supporting an indirect effect of cumulative risk on externalizing and internalizing problems through nurturant and involved parenting.

CONCLUSION

Results highlight the importance of cumulative risk during early childhood, and particularly the effect that the level of contextual risk can have on the parenting context during this developmental period.

Vulnerability as a function of individual and group resources in cumulative risk assessment

BACKGROUND

The field of risk assessment has focused on protecting the health of individual people or populations of wildlife from single risks, mostly from chemical exposure. The U.S. Environmental Protection Agency recently began to address multiple risks to communities in the "Framework for Cumulative Risk Assessment" [EPA/630/P02/001F. Washington DC:Risk Assessment Forum, U.S. Environmental Protection Agency (2003)]. Simultaneously, several reports concluded that some individuals and groups are more vulnerable to environmental risks than the general population. However, vulnerability has received little specific attention in the risk assessment literature.

OBJECTIVE

Our objective is to examine the issue of vulnerability in cumulative risk assessment and present a conceptual framework rather than a comprehensive review of the literature. In this article we consider similarities between ecologic and human communities and the factors that make communities vulnerable to environmental risks.

DISCUSSION

The literature provides substantial evidence on single environmental factors and simple conditions that increase vulnerability or reduce resilience for humans and ecologic systems. This observation is especially true for individual people and populations of wildlife. Little research directly addresses the topic of vulnerability in cumulative risk situations, especially at the community level. The community level of organization has not been adequately considered as an end point in either human or ecologic risk assessment. Furthermore, current information on human risk does not completely explain the level of response in cumulative risk conditions. Ecologic risk situations are similarly more complex and unpredictable for cases of cumulative risk.

CONCLUSIONS

Psychosocial conditions and responses are the principal missing element for humans. We propose a model for including psychologic and social factors as an integral component of cumulative risk assessment.

If cumulative risk assessment is the answer, what is the question?

Cumulative risk refers to the combined threats from exposure via all relevant routes to multiple stressors including biological, chemical, physical, and psychosocial entities. Cumulative risk assessment is a tool for organizing and analyzing information to examine, characterize, and possibly quantify the combined adverse effects on human health or ecologic resources from multiple environmental stressors. The U.S. Environmental Protection Agency (EPA) has initiated a long-term effort to develop future guidelines for cumulative risk assessment, including publication in 2003 of a framework that describes important features of the process and discusses theoretical issues, technical matters, and key definitions. The framework divides the process of cumulative risk assessment into three interrelated phases: a) planning, scoping, and problem formulation; b) analysis; and c) interpretation and risk characterization. It also discusses the additional complexities introduced by attempts to analyze cumulative risks from multiple stressors and describes some of the theoretical approaches that can be used. The development of guidelines for cumulative risk assessment is an essential element in the transition of the U.S. EPA risk assessment methodology from a narrow focus on a single stressor, end point, source, pathway, and exposure route to a broader, more holistic approach involving analysis of combined effects of cumulative exposure to multiple stressors via all relevant sources, pathways, and routes.

Assessing cumulative health risks from exposure to environmental mixtures - three fundamental questions

Differential exposure to mixtures of environmental agents, including biological, chemical, physical, and psychosocial stressors, can contribute to increased vulnerability of human populations and ecologic systems. Cumulative risk assessment is a tool for organizing and analyzing information to evaluate the probability and seriousness of harmful effects caused by either simultaneous and/or sequential exposure to multiple environmental stressors. In this article we focus on elucidating key challenges that must be addressed to determine whether and to what degree differential exposure to environmental mixtures contributes to increased vulnerability of exposed populations. In particular, the emphasis is on examining three fundamental and interrelated questions that must be addressed as part of the process to assess cumulative risk: a) Which mixtures are most important from a public health perspective? and b) What is the nature (i.e., duration, frequency, timing) and magnitude (i.e., exposure concentration and dose) of relevant cumulative exposures for the population of interest? c) What is the mechanism (e.g., toxicokinetic or toxicodynamic) and consequence (e.g., additive, less than additive, more than additive) of the mixture's interactive effects on exposed populations? The focus is primarily on human health effects from chemical mixtures, and the goal is to reinforce the need for improved assessment of cumulative exposure and better understanding of the biological mechanisms that determine toxicologic interactions among mixture constituents.

Thyroid-hormone-disrupting chemicals: evidence for dose-dependent additivity or synergism

Endocrine disruption from environmental contaminants has been linked to a broad spectrum of adverse outcomes. One concern about endocrine-disrupting xenobiotics is the potential for additive or synergistic (i.e., greater-than-additive) effects of mixtures. A short-term dosing model to examine the effects of environmental mixtures on thyroid homeostasis has been developed. Prototypic thyroid-disrupting chemicals (TDCs) such as dioxins, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers have been shown to alter thyroid hormone homeostasis in this model primarily by up-regulating hepatic catabolism of thyroid hormones via at least two mechanisms. Our present effort tested the hypothesis that a mixture of TDCs will affect serum total thyroxine (T4) concentrations in a dose-additive manner. Young female Long-Evans rats were dosed via gavage with 18 different polyhalogenated aromatic hydrocarbons [2 dioxins, 4 dibenzofurans, and 12 PCBs, including dioxin-like and non-dioxin-like PCBs] for 4 consecutive days. Serum total T4 was measured via radioimmunoassay in samples collected 24 hr after the last dose. Extensive dose-response functions (based on seven to nine doses per chemical) were determined for individual chemicals. A mixture was custom synthesized with the ratio of chemicals based on environmental concentrations. Serial dilutions of this mixture ranged from approximately background levels to 100-fold greater than background human daily intakes. Six serial dilutions of the mixture were tested in the same 4-day assay. Doses of individual chemicals that were associated with a 30% TH decrease from control (ED30), as well as predicted mixture outcomes were calculated using a flexible single-chemical-required method applicable to chemicals with differing dose thresholds and maximum-effect asymptotes. The single-chemical data were modeled without and with the mixture data to determine, respectively, the expected mixture response (the additivity model) and the experimentally observed mixture response (the empirical model). A likelihood-ratio test revealed statistically significant departure from dose additivity. There was no deviation from additivity at the lowest doses of the mixture, but there was a greater-than-additive effect at the three highest mixtures doses. At high doses the additivity model underpredicted the empirical effects by 2- to 3-fold. These are the first results to suggest dose-dependent additivity and synergism in TDCs that may act via different mechanisms in a complex mixture. The results imply that cumulative risk approaches be considered when assessing the risk of exposure to chemical mixtures that contain TDCs.

Cumulative risk of hepatocellular carcinoma in hepatitis C virus carriers: statistical estimations from cross-sectional data

The probability of developing hepatocellular carcinoma (HCC) among hepatitis C virus (HCV) carriers during their life-time is unknown. This paper addresses the estimation of the cumulative risk of HCC among HCV carriers using cross-sectional data. Age-specific prevalences of HCV carriers among the general population were estimated according to 5-year age group, based on the data of 2nd-generation anti-HCV assay in blood donors resident in Osaka (33,226 males and 29,054 females). Seropositivity of anti-HCV among 422 HCC cases, and the Osaka Cancer Registry data on HCC were used in the estimations of 5-year age-specific incidence rates of HCV-linked HCC. Using these data, the cumulative risk, i.e., the probability of contracting HCC within the following 15 years in 50-year-old HCV carriers, was estimated as 28% for males and 6% for females.

Incidence of second primary cancers in Osaka residents, Japan, with special reference to cumulative and relative risks

This study was conducted to examine the incidence rates and cumulative risks of second primary cancers in Osaka and to compare the observed number of second primary cancers with the expected number calculated using cancer incidence rates among Osaka residents. Study subjects were all reported cases aged 0-79 who were first diagnosed as having a first primary cancer between 1966-86. Incidence of second primary cancer among the study subjects was examined through to the end of 1989. The total number of study subjects was 217,307. During the follow-up period (mean duration: 3.7 years), second primary cancers developed in 5,071 patients (2.3%). Incidence of synchronous (interval < 3 months) and metachronous (interval > or = 3 months) second primary cancers increased in the later years. Incidence rates of second primary cancers were significantly associated with gender (male), age and calendar year at diagnosis of the first cancer. Based on the incidence rates, cumulative risk of developing metachronous second primary cancer was calculated. The ten-year cumulative risk was estimated as 10% for those who developed their first cancer during their sixties in 1978-83. The observed number of second primary cancers (including synchronous) was compared with the expected number. The ratios of observed-to-expected numbers were generally lower than 1.0 among those who developed their first cancer in 1966-77, while these ratios were higher than 1.0 among those who developed their first cancer in 1978-86. The ratios were much higher than 1.0 among those who developed their first cancer in their childhood and youth. Patients who had developed cancer of the colon, larynx, lung, bladder, or breast (female) showed significantly higher risk of developing second primary cancer during the period 1-4 years after diagnosis of the first cancer.