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Biomedical subjects

N Krieger

Publications and source records attributed to N Krieger.

At least 19 recordsLinked to original sources
PubMed2006

Comparing individual- and area-based socioeconomic measures for the surveillance of health disparities: A multilevel analysis of Massachusetts births, 1989-1991.

The absence of individual-level socioeconomic information in most US health surveillance data necessitates using area-based socioeconomic measures (ABSMs) to monitor health inequalities. Using the 1989-1991 birth weight data from Massachusetts, the authors compared estimates of health disparities detected with census tract- and block group-level ABSMs pertaining to poverty and education, as well as parental education, both independently and together. In separate models, adjusted for infant's sex, mother's age, and parents' race/ethnicity, worst-off categories of census tract ABSMs and parental education had a comparable birth weight deficit of approximately 70 g. Similar results were observed for low birth weight (<2,500 g), with worst-off categories of census tract ABSMs and parental education having an odds ratio of approximately 1.37 (p < 0.001). In mutually adjusted models for birth weight and low birth weight, census tract ABSMs still detected an effect estimate nearly 50% of that detected by parental education. Additionally, census tract ABSMs detected socioeconomic gradients in birth weight among births to mothers aged less than 25 years, an age group in which educational attainment is unlikely to be completed. These results suggest that aptly chosen ABSMs can be used to monitor socioeconomic inequalities in health. The risk, if any, in the absence of individual-level socioeconomic information is a conservative estimate of socioeconomic inequalities in health.

Adolescent↗
PubMed2006

Lifelong socioeconomic trajectory and premature mortality (35-65 years) in France: findings from the GAZEL Cohort Study.

BACKGROUND: Studies conducted in the UK and Scandinavia show an inverse association between lifetime socioeconomic position and adult mortality. However, there are virtually no data from other countries and few investigations have examined non-cardiovascular mortality in men and women. METHODS: Lifelong socioeconomic trajectories (father's occupation, own occupation in young adulthood and in mid-life) and premature (< or = 65 years) mortality (all-cause, smoking-related cancer, diseases of the circulatory system and external causes) in the French GAZEL Cohort Study (14,972 men and 5,598 women, followed up between 1990 and 2004) were studied. Hazard ratios (HRs) were estimated using Cox's regression models adjusted for age, marital status, tobacco smoking, alcohol consumption, body mass index, and fruit and vegetable consumption. RESULTS: Men and women who experienced lifelong disadvantage or downward intergenerational mobility were at high risk of dying prematurely compared with those with a favourable trajectory (age-adjusted HRs for all-cause mortality: cumulative disadvantage: HR 1.61, 95% confidence interval (CI) 1.26 to 2.06 in men and HR 1.95, 95% CI 1.10 to 3.47 in women; downward mobility: HR 1.87, 95% CI 1.35 to 2.58 in men and HR 2.05, 95% CI 1.12 to 3.75 in women). Associations were strongest for mortality due to chronic diseases (smoking-related cancers and diseases of the circulatory system). These associations were partly explained by marital status, body mass index, alcohol consumption, cigarette smoking, and fruit and vegetable consumption. CONCLUSIONS: In France, where the leading cause of premature death is cancer, lifelong socioeconomic position is associated with the risk of dying before the age of 65 years. Adult factors seem more relevant than childhood socioeconomic circumstances.

Adult↗
PubMed2005

Characterization of the surface enhanced raman scattering (SERS) of bacteria.

The surface enhanced Raman scattering (SERS) of a number of species and strains of bacteria obtained on novel gold nanoparticle (approximately 80 nm) covered SiO(2) substrates excited at 785 nm is reported. Raman cross-section enhancements of >10(4) per bacterium are found for both Gram-positive and Gram-negative bacteria on these SERS active substrates. The SERS spectra of bacteria are spectrally less congested and exhibit greater species differentiation than their corresponding non-SERS (bulk) Raman spectra at this excitation wavelength. Fluorescence observed in the bulk Raman emission of Bacillus species is not apparent in the corresponding SERS spectra. Despite the field enhancement effects arising from the nanostructured metal surface, this fluorescence component appears "quenched" due to an energy transfer process which does not diminish the Raman emission. The surface enhancement effect allows the observation of Raman spectra of single bacterial cells excited at low incident powers and short data acquisition times. SERS spectra of B. anthracis Sterne illustrate this single cell level capability. Comparison with previous SERS studies reveals how the SERS vibrational signatures are strongly dependent on the morphology and nature of the SERS active substrates. The potential of SERS for detection and identification of bacterial pathogens with species and strain specificity on these gold particle covered glassy substrates is demonstrated by these results.

Bacillus↗
PubMed2003

Functional properties of yam bean (Pachyrhizus erosus) starch.

The study was carried out in order to determine and establish the functional characters of starch extracted from yam bean (Pachyrhizus erosus (L) Urban) compared with cassava starch. Yam bean is a tropical tuber legume easily grown and holds a great potential as a new source of starch. Yam bean starch shows functional properties which are peculiar to those of most starch root crops. Gelatinization temperature (53-63 degrees C) and the pasting temperature (64.5 degrees C) are less than those of cereal starch, however, the swelling power is high (54.4 g gel/g dried starch). Yam bean starch paste presents a high viscosity profile, high retrogradation tendency and low stability on cooking. The functional properties of yam bean starch, similar to those of cassava starch, allows yam bean to be used as a potential new source of starch.

Gels↗
PubMed2003

Choosing area based socioeconomic measures to monitor social inequalities in low birth weight and childhood lead poisoning: The Public Health Disparities Geocoding Project (US).

STUDY OBJECTIVES: : To determine which area based socioeconomic measures can meaningfully be used, at which level of geography, to monitor socioeconomic inequalities in childhood health in the US. DESIGN: Cross sectional analysis of birth certificate and childhood lead poisoning registry data, geocoded and linked to diverse area based socioeconomic measures that were generated at three geographical levels: census tract, block group, and ZIP code. SETTING: Two US states: Massachusetts (1990 population=6,016,425) and Rhode Island (1990 population=1,003,464). PARTICIPANTS: All births born to mothers ages 15 to 55 years old who were residents of either Massachusetts (1989-1991; n=267,311) or Rhode Island (1987-1993; n=96 138), and all children ages 1 to 5 years residing in Rhode Island who were screened for lead levels between 1994 and 1996 (n=62,514 children, restricted to first test during the study period). MAIN RESULTS: Analyses of both the birth weight and lead data indicated that: (a) block group and tract socioeconomic measures performed similarly within and across both states, while ZIP code level measures tended to detect smaller effects; (b) measures pertaining to economic poverty detected stronger gradients than measures of education, occupation, and wealth; (c) results were similar for categories generated by quintiles and by a priori categorical cut off points; and (d) the area based socioeconomic measures yielded estimates of effect equal to or augmenting those detected, respectively, by individual level educational data for birth outcomes and by the area based housing measure recommended by the US government for monitoring childhood lead poisoning. CONCLUSIONS: Census tract or block group area based socioeconomic measures of economic deprivation could be meaningfully used in conjunction with US public health surveillance systems to enable or enhance monitoring of social inequalities in health in the United States.

Adolescent↗
PubMed2003

Assessing health impact assessment: multidisciplinary and international perspectives.

Health impact assessment (HIA) seeks to expand evaluation of policy and programmes in all sectors, both private and public, to include their impact on population health. While the idea that the public's health is affected by a broad array of social and economic policies is not new and dates back well over two centuries, what is new is the notion-increasingly adopted by major health institutions, such as the World Health Organisation (WHO) and the United Kingdom National Health Services (NHS)-that health should be an explicit consideration when evaluating all public policies. In this article, it is argued that while HIA has the potential to enhance recognition of societal determinants of health and of intersectoral responsibility for health, its pitfalls warrant critical attention. Greater clarity is required regarding criteria for initiating, conducting, and completing HIA, including rules pertaining to decision making, enforcement, compliance, plus paying for their conduct. Critical debate over the promise, process, and pitfalls of HIA needs to be informed by multiple disciplines and perspectives from diverse people and regions of the world.

Evidence-Based Medicine↗
PubMed2002

The potential for establishment of axial temperature profiles during solid-state fermentation in rotating drum bioreactors.

The mixing and heat transfer phenomena within rotating drum bioreactors (RDBs) used for solid-state fermentation processes are poorly studied. The potential for the establishment of axial temperature gradients within the substrate bed was explored using a heat transfer model. For growth of Aspergillus oryzae on wheat bran within a 24 L RDB with air at a superficial velocity of 0.0023 m s(-1) and 15% relative humidity, the model predicts an axial gradient between the air inlet and outlet of 2 degrees C during rapid growth, compared to experimental axial temperature gradients of between 1 and 4 degrees C. Undesirably high temperatures occur throughout the bed under these operating conditions, but the model predicts that good temperature control can be achieved using humid air (90% relative humidity) at superficial velocities of 1 m s(-1) for a 204 L RDB. For a 2200 L RDB, good temperature control is predicted with superficial velocities as low as 0.4 m s(-1) with the airflow being switched from 90% to 15% relative humidity whenever the temperature at the outlet end of the drum exceeds the optimal temperature for growth. This work suggests that significant axial temperature gradients can arise in those RDBs that lack provision for axial mixing. It is therefore advisable to use angled lifters within RDBs to promote axial mixing.

Air Movements↗
PubMed2002

Lifetime socioeconomic position in relation to onset of perimenopause.

STUDY OBJECTIVE: To assess the association between lifetime socioeconomic position and onset of perimenopause. DESIGN: Prospective cohort study. SETTING: Boston, Massachusetts. PARTICIPANTS: 603 premenopausal women aged 36-45 years at baseline who completed a cross sectional survey on childhood and adult socioeconomic position. MAIN OUTCOME MEASURES: Time to perimenopause, defined as time in months from baseline interview to a woman's report of (1) an absolute change of at least seven days in menstrual cycle length from baseline or subjective report of menstrual irregularity; (2) a change in menstrual flow amount or duration; or (3) cessation of periods for at least three months, whichever came first. MAIN RESULTS: Incidence of perimenopause was 1.75 times higher (95%CI 1.10 to 2.79) and median age at onset was 1.2 years younger (44.7 v 45.9 years) for women reporting childhood and adult economic distress compared with women reporting no lifetime economic distress. After adjustment for age, race/ethnicity, age at menarche, parity, oral contraceptive use, family history of early menopause, depression, smoking, and body mass index, the association weakened (incidence rate ratio (IRR)=1.59; 95%CI 0.97 to 2.61). Inverse associations were observed for most, but not all, measures of educational level. Measures of current household income were not associated with risk of perimenopause. CONCLUSIONS: This study suggests that adverse socioeconomic conditions across the lifespan, when measured in terms of economic hardship and low educational attainment, may be associated with an increased rate of entry into perimenopause.

Adult↗
PubMed2001

Adult onset of major depressive disorder in relation to early life violent victimisation: a case-control study.

BACKGROUND: Major depressive disorder is a significant cause of morbidity among women in the USA. Women are twice as likely as men to be diagnosed with major depressive disorder, yet no known risk factors can account for this sex difference. We aimed to assess violent victimisation as a risk factor for depression in women. METHODS: We undertook a case-control study to assess the association between violent victimisation early in life and major depressive disorder in women. We randomly selected a population-based sample of women, aged 36-45 years, from the greater Boston area. In 1999, 236 cases and 496 controls (n=732) completed a self-administered questionnaire designed to ascertain a lifetime history of exposure to violent victimisation. Our main outcome measure was major depressive disorder, assessed by structured clinical interview for Diagnostic Statistical Manual IV (DSM-IV) criteria. FINDINGS: 363 (50%) of 732 respondents reported experience or fear of abuse as a child or adolescent. 68 were excluded because they reported violence as an adult only. Compared with women who reported no abuse, risk of depression was increased in women who reported any abuse as a child or adolescent (relative risk 2.5, 95% CI 1.9-3.0), physical abuse only (2.4, 1.8-3.0), sexual abuse only (1.8, 1.2-2.8), and both physical and sexual abuse (3.3, 2.5-4.1). Severity of abuse had a linear dose-response relation with depression. INTERPRETATION: Our results suggest a positive association between violent victimisation early in life and major depressive disorder in women.

Adult↗
PubMed2001

Class inequalities in women's health: combined impact of childhood and adult social class--a study of 630 US women.

To assess contributions of childhood and adult social class to class gradients in women's health, the authors used gender-neutral household measures of class position in a retrospective cohort study of 630 women enrolled in Examination II of the Kaiser Permanente Women Twins Study (1989-1990, Oakland, CA). The age-adjusted odds of reporting fair or poor health was 2.3 times higher (95% confidence interval (CI)=1.2-4.1), using adult class measures, among women categorized as working class vs non-working class/professional. When stratified by childhood social class, however, the elevated risk of fair/poor health among adult working class compared to non-working class/professional women was evident only among those with a non-working class/professional childhood. Similarly, a working class tendency (based on adult class position) towards elevated levels of low density lipoprotein (LDL) cholesterol (odds ratio (OR)=1.5, 95% CI=0.9-2.7) and post-load glucose (OR=1.8, 95% CI=1.0-3.3) was apparent only among women who were non-working class in childhood. These results indicate that both childhood and adult class position influence class gradients in women's health in the United States.

Adolescent↗
PubMed2001

Maternal experiences of racism and violence as predictors of preterm birth: rationale and study design.

Chronic psychological stress may raise the risk of preterm delivery by raising levels of placental corticotropin-releasing hormone (CRH). Women who have been the targets of racism or personal violence may be at particularly high risk of preterm delivery. The aims of this study are to examine the extent to which: (1) maternal experiences of racism or violence in childhood, adulthood, or pregnancy are associated with the risk of preterm birth; (2) CRH levels are prospectively associated with risk of preterm birth; and (3) CRH levels are associated with past and current maternal experiences of racism or violence. We have begun to examine these questions among women enrolled in Project Viva, a Boston-based longitudinal study of 6000 pregnant women and their children.

Adult↗
PubMed2001

Ovarian function in late reproductive years in relation to lifetime experiences of abuse.

The objective of this study was to investigate the relation between violence victimization and levels of ovarian hormones during women's late reproductive years, as measured by serum levels of follicle-stimulating hormone and estradiol, which respectively rise and fall with onset of menopause. In March 1999, 732 women 36-45 years of age from the Harvard Study of Moods and Cycles cohort completed a survey of lifetime experiences of physical and sexual harm. Follicle-stimulating hormone and estradiol levels were measured during the menstrual period after entry into the cohort. Associations for violence and follicle-stimulating hormone and estradiol levels were estimated using crude and adjusted risk differences. Overall, women who experienced abuse during childhood or adolescence relative to never-abused women had a slight positive association of violence with high follicle-stimulating hormone. However, a positive association with high follicle-stimulating hormone was not observed among women whose first abuse occurred during adulthood. Age stratification indicated modification of the association between violence and low estradiol. Women 36-40 years of age had no evidence of a positive association between violence before adulthood and low estradiol, whereas first violence in adulthood was associated with an 11% increase in the estimate of risk difference [95% confidence limits (CL) = -0.14, 0.36]. Among women 41-45 years, there was a 17-23% increase in the estimate of risk difference for low estradiol, regardless of life stage at first experience of abuse (before adulthood, 95% CL = 0.06, 0.28; during adulthood, 95% CL = 0.01, 0.46). This investigation supports the credibility of a hypothesis that physical and sexual abuse may lead to neuroendocrine disruption, thereby affecting ovarian function and potentially leading to altered age at perimenopausal transition.

Adult↗
PubMed2001

Enhancement of hepatitis C virus RNA replication by cell culture-adaptive mutations.

Studies of the Hepatitis C virus (HCV) replication cycle have been made possible with the development of subgenomic selectable RNAs that replicate autonomously in cultured cells. In these replicons the region encoding the HCV structural proteins was replaced by the neomycin phosphotransferase gene, allowing the selection of transfected cells that support high-level replication of these RNAs. Subsequent analyses revealed that, within selected cells, HCV RNAs had acquired adaptive mutations that increased the efficiency of colony formation by an unknown mechanism. Using a panel of replicons that differed in their degrees of cell culture adaptation, in this study we show that adaptive mutations enhance RNA replication. Transient-transfection assays that did not require selection of transfected cells demonstrated a clear correlation between the level of adaptation and RNA replication. The highest replication level was found with an adapted replicon carrying two amino acid substitutions located in NS3 and one in NS5A that acted synergistically. In contrast, the nonadapted RNA replicated only transiently and at a low level. The correlation between the efficiency of colony formation and RNA replication was corroborated with replicons in which the selectable marker gene was replaced by the gene encoding firefly luciferase. Upon transfection of naive Huh-7 cells, the levels of luciferase activity directly reflected the replication efficiencies of the various replicon RNAs. These results show that cell culture-adaptive mutations enhance HCV RNA replication.

Adaptation, Physiological↗
PubMed2001

Sequences in the 5' nontranslated region of hepatitis C virus required for RNA replication.

Sequences in the 5' and 3' termini of plus-strand RNA viruses harbor cis-acting elements important for efficient translation and replication. In case of the hepatitis C virus (HCV), a plus-strand RNA virus of the family Flaviviridae, a 341-nucleotide-long nontranslated region (NTR) is located at the 5' end of the genome. This sequence contains an internal ribosome entry site (IRES) that is located downstream of an about 40-nucleotide-long sequence of unknown function. By using our recently developed HCV replicon system, we mapped and characterized the sequences in the 5' NTR required for RNA replication. We show that deletions introduced into the 5' terminal 40 nucleotides abolished RNA replication but only moderately affected translation. By generating a series of replicons with HCV-poliovirus (PV) chimeric 5' NTRs, we could show that the first 125 nucleotides of the HCV genome are essential and sufficient for RNA replication. However, the efficiency could be tremendously increased upon the addition of the complete HCV 5' NTR. These data show that (i) sequences upstream of the HCV IRES are essential for RNA replication, (ii) the first 125 nucleotides of the HCV 5' NTR are sufficient for RNA replication, but such replicon molecules are severely impaired for multiplication, and (iii) high-level HCV replication requires sequences located within the IRES. These data provide the first identification of signals in the 5' NTR of HCV RNA essential for replication of this virus.

5' Untranslated Regions↗