Nonlocal problems for quasilinear functional partial differential equations of first order

Existence and uniqueness of almost everywhere solutions of nonlocal problems to functional partial differential systems in diagonal form are investigated. The proof is based on the characteristics and fixed point methods

Cardiovascular disease in a cohort exposed to the 1940-45 Channel Islands occupation

BACKGROUND To clarify the nature of the relationship between food deprivation/undernutrition during pre- and postnatal development and cardiovascular disease (CVD) in later life, this study examined the relationship between birth weight (as a marker of prenatal nutrition) and the incidence of hospital admissions for CVD from 1997–2005 amongst 873 Guernsey islanders (born in 1923–1937), 225 of whom had been exposed to food deprivation as children, adolescents or young adults (i.e. postnatal undernutrition) during the 1940–45 German occupation of the Channel Islands, and 648 of whom had left or been evacuated from the islands before the occupation began. METHODS Three sets of Cox regression models were used to investigate (A) the relationship between birth weight and CVD, (B) the relationship between postnatal exposure to the occupation and CVD and (C) any interaction between birth weight, postnatal exposure to the occupation and CVD. These models also tested for any interactions between birth weight and sex, and postnatal exposure to the occupation and parish of residence at birth (as a marker of parish residence during the occupation and related variation in the severity of food deprivation). RESULTS The first set of models (A) found no relationship between birth weight and CVD even after adjustment for potential confounders (hazard ratio (HR) per kg increase in birth weight: 1.12; 95% confidence intervals (CI): 0.70 – 1.78), and there was no significant interaction between birth weight and sex (p = 0.60). The second set of models (B) found a significant relationship between postnatal exposure to the occupation and CVD after adjustment for potential confounders (HR for exposed vs. unexposed group: 2.52; 95% CI: 1.54 – 4.13), as well as a significant interaction between postnatal exposure to the occupation and parish of residence at birth (p = 0.01), such that those born in urban parishes (where food deprivation was worst) had a greater HR for CVD than those born in rural parishes. The third model (C) found no interaction between birth weight and exposure to the occupation (p = 0.43). CONCLUSION These findings suggest that the levels of postnatal undernutrition experienced by children, adolescents and young adults exposed to food deprivation during the 1940–45 occupation of the Channel Islands were a more important determinant of CVD in later life than the levels of prenatal undernutrition experienced in utero prior to the occupatio

Intrauterine environments and breast cancer risk: meta-analysis and systematic review

INTRODUCTION: Various perinatal factors, including birth weight, birth order, maternal age, gestational age, twin status, and parental smoking, have been postulated to affect breast cancer risk in daughters by altering the hormonal environment of the developing fetal mammary glands. Despite ample biologic plausibility, epidemiologic studies to date have yielded conflicting results. We investigated the associations between perinatal factors and subsequent breast cancer risk through meta-analyses. METHODS: We reviewed breast cancer studies published from January 1966 to February 2007 that included data on birth weight, birth order, maternal age, gestational age, twin status, and maternal or paternal smoking. Meta-analyses using random effect models were employed to summarize the results. RESULTS: We found that heavier birth weights were associated with increased breast cancer risk, with studies involving five categories of birth weight identifying odds ratios (ORs) of 1.24 (95% confidence interval [CI] 1.04 to 1.48) for 4,000 g or more and 1.15 (95% CI 1.04 to 1.26) for 3,500 g to 3,999 g, relative to a birth weight of 2,500 to 2,599 g. These studies provided no support for a J-shaped relationship of birthweight to risk. Support for an association with birthweight was also derived from studies based on three birth weight categories (OR 1.15 [95% CI 1.01 to 1.31] for > or =4,000 g relative to or =3,000 g relative to <3,000 g). Women born to older mothers and twins were also at some increased risk, but the results were heterogeneous across studies and publication years. Birth order, prematurity, and maternal smoking were unrelated to breast cancer risk. CONCLUSION: Our findings provide some support for the hypothesis that in utero exposures reflective of higher endogenous hormone levels could affect risk for development of breast cancer in adulthood

Hypertension and breast cancer risk in a 19-year foIlow-up study (the DOM cohort)

Background To investigate whether hypertension and the use of anti-hypertensive drugs are associated with breast cancer risk.Methods This was a prospective study of 11 011 women living in Utrecht, the Netherlands, aged 50-65 years at enrolment in a breast cancer screening project (DOM cohort). Women attended screening rounds between 1974 and 1985 at which blood pressure was measured and information on drug use and breast cancer risk factors was ascertained. Since 1974 (median follow-up time 19 years), information on breast cancer occurrence and death has been registered, Hypertension was defined as a systolic blood pressure &gt; 160 mmHg or a diastolic blood pressure &gt; 95 mmHg or current use of drugs for the indication hypertension, Cox's regression analysis was used to investigate the association between hypertension (treated or untreated) and subsequent breast cancer risk, Analyses were adjusted for age, body mass index, height, parity, familial breast cancer, smoking and oral contraceptive use,Results A total of 523 women were diagnosed with breast cancer, Hypertensive women experienced a statistically significant increased breast cancer risk of 23% (age-adjusted hazard ratio (HRa) = 1.23; 95% confidence interval (CI) 1.01-1.49), After adjustment for all confounders, the increase was 14% (HR =1.14; 95% CI 0.93-1.40). The decline in risk was mainly attributable to the effect of BMI, The risk was similar in treated (HR = 1.22; 95% CI 0.91-1.63) and untreated hypertensive women (HR = 1.13; 95% CI 0.91-1.40),Conclusion These results do not support an association between hypertension and breast cancer, and if there is a link, it is likely to be positive and relatively small in size (+14%), This relation, if present, is not attributable to antihypertensive drugs, since the relation is also present in non-drug users, J Hypertens 2000, 18:249-254 (C) Lippincott Williams &amp; Wilkins.</p