Is enhanced fetal growth a risk factor for the development of atopy or asthma?

BACKGROUND: The aetiological factors underlying the worldwide increase in the prevalence of asthma and the international patterns of the prevalence of asthma are not well understood. This has led to consideration of factors such as fetomaternal health which may programme the initial susceptibility to allergic sensitisation, or contribute to the development of asthma independently of sensitisation. METHODS: A number of epidemiological studies have examined the relationship between birth anthropometric measures (as a marker of fetomaternal health) and the subsequent development of asthma and atopy in childhood or adult life. RESULTS: Some, but not all of these studies have reported a relationship between enhanced fetal growth and an increased risk of asthma and/or atopy. CONCLUSION: These findings raise the hypothesis that factors responsible for fetal growth may also lead to programming of the developing respiratory or immune systems, predisposing to the subsequent development of asthma and/or atopy. This hypothesis may explain, in part, the increasing prevalence of asthma and atopy over recent decades, which has occurred concurrently with secular trends for improved fetomaternal health, as measured by anthropometric measurements at birth.     

Is obesity a risk factor for childhood asthma?

Background: In adolescents and adults, an association between obesity and asthma was found in females. Does this sex‐specific association already exist in young children? Methods: Questionnaire data on 9357 5‐ and 6‐year‐old German children were collected in 1997 in two rural regions in Bavaria. The diagnosis of asthma, hay fever, and eczema was ascertained with the ISAAC core and other validated questions. Overweight was defined by a BMI of >90th and ≤97th percentile and obesity by a BMI of >97th percentile. Results: The lifetime prevalence of doctor's diagnosed asthma in girls was 3.5% (95% CI 2.9–4.1%) for normal weight, 5.8% (95% CI 3.2–8.4%) for overweight, and 10.3% (95% CI 5.3–15.2%) for obesity, whereas no relation to weight was found in boys. Hay fever and eczema were unrelated to weight in girls and boys. The adjusted odds ratio for asthma in girls was 2.12 (95% CI 1.22–3.68) for overweight and 2.33 (95% CI 1.13–4.82) for obesity. Conclusions: A sex‐specific association with doctor's diagnosed asthma was also observed in girls at school entry. Since this association was confined to doctor's diagnosed asthma in the absence of other atopic conditions, and no association with other atopic manifestations was found, we hypothesize that this association is related to factors other than atopic sensitization.     

To what extent is allergen exposure a risk factor for the development of allergic disease?

The role of allergen exposure in the development of allergic disease has been a matter of considerable debate, and our understanding of the importance of allergens has evolved over the last 25 years. Several observational and primary prevention studies have investigated these relationships, and different studies reported inconsistent, and sometimes opposite findings. It has to be emphasized that a clear understanding of how aeroallergen exposure occurs, and accurate and reproducible measurement of exposure are essential prerequisites for understanding the role of exposure. However, our current understanding of how we get exposed to allergens is not based on solid evidence, but on a number of assumptions, and we urgently need to develop better proxy measures (or indices) of exposure. In addition, the relative importance of the timing of exposure (e.g. early compared to exposure in later life) is unknown. It is also unclear which route of exposure is the most relevant (e.g. inhaled vs. oral vs. transcutaneous). Available data suggest that the dose–response relationship between allergen exposure and allergic disease may differ between different allergens, dose ranges and exposure patterns, and these relationships may further differ between different populations and geographical areas. It is increasingly clear that childhood asthma and atopy are not single phenotypes, and it is likely that allergen exposure has different effect on distinct subgroups under the umbrella terms of ‘sensitization’ and ‘asthma’. Susceptibility to allergen exposure, other environmental exposures and their interactions may also differ between individuals with different genetic predispositions. However, the precise nature of these complex relationships is unclear. We need a holistic approach offered by systems biology, with integration of information on the standardized and reliable measures of exposures (including allergens and other relevant exposures) with genetic and biological data to fully understand the role of allergens in the development of allergic disease.     

Is allergic rhinitis a trivial disease?

BACKGROUND:

Asthma and rhinitis often coexist, which potentially increases the disease severity and can negatively impact a patients'' quality of life. However, there are few reports based on data obtained from the International Study of Asthma and Allergies in Childhood examining asthma severity in combination with rhinitis-related symptoms.

OBJECTIVE:

To demonstrate whether current rhinitis and current rhinoconjunctivitis are associated with the development of asthma or its increasing severity in Brazilian adolescents.

METHODS:

The prevalence of current asthma was correlated with the prevalence of current rhinitis and current rhinoconjunctivitis in adolescents (13 to 14 year olds) from 16 Brazilian centers (based on Spearman''s rank correlation index). The influence of current rhinitis and current rhinoconjunctivitis on asthma presentation was also evaluated using the chi-squared test and was expressed as odds ratios with 95% confidence intervals (95%CI).

RESULTS:

A significant positive correlation was observed between the prevalence of current asthma and current rhinitis (rs = 0.82; 95%CI: 0.60–0.93, p<0.0001) and between the prevalence of current asthma and current rhinoconjunctivitis (rs = 0.75; 95%CI: 0.47–0.89, p<0.0001). Current rhinitis was associated with a significantly increased risk of current asthma and of more severe asthma. Similar results were observed for current rhinoconjunctivitis.

CONCLUSION:

In this epidemiologic study of Brazilian adolescents, the presence of current rhinitis and current rhinoconjunctivitis was associated with a high risk of developing asthma and increased asthma severity. The mutual evaluation of rhinitis and asthma is necessary to establish an adequate treatment plan.     

Is the prevalence of adult asthma and allergic rhinitis still increasing? Results of an Italian study

BACKGROUND: The prevalence of asthma and allergic rhinitis has increased worldwide during the 1970s and 1980s. OBJECTIVE: This study was aimed at evaluating whether the increasing trend in prevalence persisted during the 1990s in the young adult Italian population. METHODS: In 1998 to 2000 a screening questionnaire was sent by mail to a general population sample aged 20 to 44 years; nonresponders were contacted again first by mail and then by phone, achieving a final response rate of 78.1% (6876 of 8800). Prevalence estimates, adjusted to correct for nonresponse bias, were compared with those recorded in Italy in 1991 to 1993 during the European Community Respiratory Health Survey, when response rate had been slightly higher (87.6%). Temporal variations in symptom prevalence were analyzed by a logistic regression model, controlling for sex, age, site of residence (urban vs suburban areas), season of response, response rate, and type of contact (mail vs phone). RESULTS: The prevalence of asthma attacks did not vary significantly from 1991 to 1993 (3.6%) to 1998 to 2000 (3.2%) (P =.188). The prevalence of asthma-like symptoms (wheezing, chest tightness, shortness of breath) tended to decrease in the age classes of 32.5 to 45 years, while increasing in the youngest age class (20 to 26 years). A clear-cut increase from 15.4% to 18.3% was observed for the prevalence of allergic rhinitis (P <.001), whereas the proportion of people under antiasthmatic treatment increased in suburban areas but not in urban areas (interaction time-site of residence, P <.001). CONCLUSION: Asthma prevalence has not increased during the last decade in Italy. The persistence of an increasing trend in allergic rhinitis prevalence deserves attention.     

Is rheumatoid arthritis a risk factor for oral bisphosphonate-induced osteonecrosis of the jaws?

Bisphosphonate-related osteonecrosis of the jaws is a relevant side-effect of these drugs that has been generating a great concern through increasing reports, worldwide, of this bone necrosis. Among several BRONJ hypothetical co-factors that could play a role in BRONJ pathogenesis, rheumatoid arthritis (RA) has been included as a relevant risk factor for BRONJ; however, until now the relationship between these diseases has not been fully explained. Thus, the purpose of this paper is to establish hypothetical factors that could link these two diseases, considering mainly inflammatory components and the organism effects of medicines used to treat RA, particularly steroids and methotrexate (MTX).     

Is behavioral inhibition a risk factor for depression?

BACKGROUND: Several studies have reported an observed relationship between a behaviorally inhibited temperament early in life and subsequent clinical anxiety, but few have explored the relationship between early inhibition and depression. METHODS: In a cross-sectional survey of non-clinical adults we examined the relationship between retrospectively reported childhood behavioral inhibition and lifetime depression. We then examined the mediating role of social anxiety and childhood relational stress factors. RESULTS: Subjects who qualified for a lifetime episode of depression also reported significantly more childhood inhibition, particularly if they had a juvenile onset depression (i.e., by age 16). Further analyses revealed that social anxiety mediated the link between reported childhood inhibition and later depression, and highlighted the additional meditating effect of parental influences. CONCLUSION: Any relationship between an early inhibited temperament and later depression, may in fact be dependent upon the presence of clinically meaningful social anxiety.     

Is infection a major risk factor for preeclampsia?

Recently in an open population-based program composed of 15 354 pregnant women in Colombia we applied a biopsychosocial risk model, which permitted us to identify pregnant women at high risk of preeclampsia. 1443 (9.4%) of patients at high risk for developing preeclampsia received 450 mg of linoleic acid, and 1.5 g/day of calcium. Bacteriuria was identified in 1766 (11.5%) and vaginal infections in 2150 (14.0%) of the pregnant women. These women received oral antibiotics for 10 days. The incidence of low birthweight, preterm delivery and preeclampsia were reduced by 53% (6.2% vs 13.2%), 64.7% (1.8% vs 5.1%), and 52.5% (3.8% vs 8.0%) respectively, when compared with the incidence of the preceding five years. We believe that these dramatic reductions were due to early identification of risk factors, administration of nutritional supplements and principally by treatment of asymptomatic infections. Unfortunately, because of the study design it is not possible to confirm that infection was the major risk factor for preeclampsia in our population. However, we hypothesize that chronic subclinical infections may cause increased maternal cytokine levels sufficient to affect vascular endothelial function, and so prime individuals for the subsequent development of preeclampsia. This hypothesis can be tested in a more appropriately designed clinical trial to assess whether there is a relationship between infection, inflammation and preeclampsia.     

Is factor V Leiden a risk factor for fetal loss?

A successful pregnancy is dependent on the development of adequate placental circulation. The abnormalities of placental vasculature may result in a number of gestational pathologies, including fetal loss. The aim of our study was to determine whether women with f V Leiden are at an increased risk of pregnancy loss. For this purpose we assessed three groups of women. In a prospective group we examined 30 females with spontaneous abortions for f V Leiden. In a retrospective group we assessed the frequency of abortions in 80 women (172 pregnancies) with f V Leiden (72 heterozygous, 8 homozygous) from 57 unrelated families. In a control group we evaluated the frequency of abortions in 45 women without f V Leiden. Factor V Leiden was found in 3% of women in the 1st group. Fetal loss occurred in 10% of women in the 2nd group and in 9% in the 3rd group. Factor V Leiden was not found to be a risk factor for fetal loss in our study group.     

Fast foods – are they a risk factor for asthma?

BACKGROUND: Lifestyle changes over the last 30 years are the most likely explanation for the increase in allergic disease over this period. AIM: This study tests the hypothesis that the consumption of fast food is related to the prevalence of asthma and allergy. METHODS: As part of the International Study of Asthma and Allergies in Childhood (ISAAC) a cross-sectional prevalence study of 1321 children (mean age = 11.4 years, range: 10.1-12.5) was conducted in Hastings, New Zealand. Using standard questions we collected data on the prevalence of asthma and asthma symptoms, as well as food frequency data. Skin prick tests were performed to common environmental allergens and exercise-induced bronchial hyperresponsiveness (BHR) was assessed according to a standard protocol. Body mass index (BMI) was calculated as weight/height2 (kg/m2) and classified into overweight and obese according to a standard international definition. RESULTS: After adjusting for lifestyle factors, including other diet and BMI variables, compared with children who never ate hamburgers, we found an independent risk of hamburger consumption on having a history of wheeze [consumption less than once a week (OR = 1.44, 95% CI: 1.06-1.96) and 1+ times a week (OR = 1.65, 95% CI: 1.07-2.52)] and on current wheeze [consumption less than once a week (OR = 1.17, 95% CI: 0.80-1.70) and 1+ times a week (OR = 1.81, 95% CI: 1.10-2.98)]. Takeaway consumption 1+ times a week was marginally significantly related to BHR (OR = 2.41, 95% CI: 0.99-5.91). There was no effect on atopy. CONCLUSIONS: Frequent consumption of hamburgers showed a dose-dependent association with asthma symptoms, and frequent takeaway consumption showed a similar association with BHR.     

Is infertility a risk factor for impaired male fertility?

BACKGROUND: Previous research has suggested an interaction between distress and male fertility. The present longitudinal study sought to deliver evidence for a negative impact of distress due to infertility on sperm concentration. METHODS: The sample consisted of 120 patients who twice visited an andrological clinic on their own initiative for fertility work-ups. Baseline and follow-up examinations were at least 6 months apart. Prior to each fertility work-up, patients completed a questionnaire assessing distress due to infertility. RESULTS: Path analyses revealed that the level of infertility distress at follow-up has a negative impact on the change in sperm quality from baseline to follow-up assessment. Distress scores were highly stable. As a consequence, the level of distress at baseline assessment provided only little additional information for the changes in sperm concentration. Further analysis suggested that the fertility status had no impact on infertility distress. CONCLUSION: The present study delivers the strongest evidence to date that distress due to infertility is a significant risk factor for a decrease in sperm quality.     

Aging of the immune system: a risk factor for autoimmunity?

Aging of the immune system, or immunosenescence, is characterized by changes in T cell subsets, cellular and molecular level alterations and thymic atrophy, resulting in a decline of T and B cell function. These alterations have been shown to be accompanied by a loss of ability to recognize "self" and "foreign" antigens. Therefore the development of autoimmune responses like production of autoantibodies has been hypothesized to be secondary to thymus involution with a decline of na?ve T cells and accumulation of clonal T cells with activation due to "neoantigens" during the aging process. Altered apoptosis and altered T cell homeostasis have been emphasized to promote a chronic inflammatory state and lead to the concept of a immune-risk phenotype. However, it has to be proven which kinds of mechanisms turn the immune system to manifest autoimmune disease and how speculated defects in T cell differentiation and interaction leading to premature aging of the immune system may contribute to the development of autoimmune diseases.