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1.
J Dairy Sci ; 103(7): 6612-6626, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32307158

ABSTRACT

Adrenal responsiveness was tested in nonpregnant, lactating Holstein dairy cows fed diets supplemented with OmniGen-AF (OG; Phibro Animal Health Corp., Teaneck, NJ), an immune modulator, and in nonsupplemented control (CON) cows following bolus infusions of a combination of corticotropin-releasing hormone (CRH; 0.3 µg/kg of BW) and arginine vasopressin (VP; 1.0 µg/kg of BW) or ACTH (0.1 IU/kg of BW) in 2 environments: thermoneutral [TN; temperature-humidity index (THI) <60] for 24 h/d and heat stress (HS; THI >68 for 17 h/d). Cows (506) were initially fed OG (n = 254) or CON (n = 252) diets for 44 d before selection of a subgroup of cows (n = 12; 6 OG, 6 CON) for the study. The 2 subgroups were balanced for parity, milk yield, and days in milk. All cows were transported to and housed in 2 environmentally controlled rooms at the University of Arizona Agricultural Research Complex (Tucson). Cows were given 3 d to acclimate to the rooms and then underwent 12 d of TN conditions and then 8 d of HS conditions for a total of 24 d on experiment. Cows were infused with CRH-VP on d 9 of TN and on d 1 of HS and with ACTH on d 10 of TN and on d 2 of HS. Hormone infusions took place at 1000 h (0 h) on each infusion day. Blood samples, taken in 30-min intervals, were first collected at 0800 h (-2 h) and were drawn until 1800 h (8 h). Before infusion, serum progesterone was elevated in OG cows compared with CON cows. Infusion of releasing factors (CRH-VP or ACTH) caused increases in serum cortisol and progesterone, but cortisol release was greater in CON cows than in OG cows during HS, whereas progesterone did not differ between the 2 treatments. Serum ACTH increased following infusion of releasing factors, but this increase was greater following CRH-VP infusion than ACTH infusion. Serum bovine corticosteroid-binding globulin also increased following infusion of releasing factors in both treatment groups, but this increase was greater during HS in cows fed OG. The free cortisol index (FCI) increased following CRH-VP and ACTH and was higher in HS than in TN for both OG and CON cows. However, the FCI response was blunted in OG cows compared with CON cows during HS. Heat stress enhanced the adrenal response to releasing factors. Additionally, the adrenal cortisol and FCI response to releasing factors was reduced during acute heat stress in cows fed OG. Collectively, these data suggest that OG supplementation reduced the adrenal responsiveness to factors regulating cortisol secretion during acute HS.


Subject(s)
Adrenocorticotropic Hormone/pharmacology , Cattle/physiology , Corticotropin-Releasing Hormone/pharmacology , Dietary Supplements/analysis , Milk/metabolism , Vasopressins/pharmacology , Animals , Diet/veterinary , Female , Heat-Shock Response , Humidity , Hydrocortisone/blood , Lactation , Parity , Pregnancy , Progesterone/blood
2.
BMC Fam Pract ; 20(1): 161, 2019 11 21.
Article in English | MEDLINE | ID: mdl-31752693

ABSTRACT

BACKGROUND: Primary care providers (PCPs) have always played an important role in cancer diagnosis. There is increasing awareness of the importance of their role during treatment and survivorship. We examined changes in PCP utilization from pre-diagnosis to survival for women diagnosed with breast cancer, factors associated with being a high user of primary care, and variation across four Canadian provinces. METHODS: The cohorts included women 18+ years of age diagnosed with stage I-III invasive breast cancer in years 2007-2012 in British Columbia (BC), Manitoba (MB), Ontario (ON), and Nova Scotia (NS) who had surgery plus adjuvant chemotherapy and were alive 30+ months after diagnosis (N = 19,589). We compared the rate of PCP visits in each province across phases of care (pre-diagnosis, diagnosis, treatment, and survival years 1 to 4). RESULTS: PCP use was greatest during treatment and decreased with each successive survival year in all provinces. The unadjusted difference in PCP use between treatment and pre-diagnosis was most pronounced in BC where PCP use was six times higher during treatment than pre-diagnosis. Factors associated with being a high user of primary care during treatment included comorbidity and being a high user of care pre-diagnosis in all provinces. These factors were also associated with being a higher user of care during diagnosis and survival. CONCLUSIONS: Contrary to the traditional view that PCPs focus primarily on cancer prevention and early detection, we found that PCPs are involved in the care of women diagnosed with breast cancer across all phases of care.


Subject(s)
Breast Neoplasms/therapy , Primary Health Care , Adolescent , Adult , Aged , Breast Neoplasms/diagnosis , Breast Neoplasms/mortality , Canada , Female , Humans , Longitudinal Studies , Middle Aged , Patient Acceptance of Health Care/statistics & numerical data , Primary Health Care/statistics & numerical data , Young Adult
3.
Curr Oncol ; 26(5): e624-e639, 2019 10.
Article in English | MEDLINE | ID: mdl-31708656

ABSTRACT

Background: Chemotherapy has improved outcomes in early-stage breast cancer, but treatment practices vary, and use of acute care is common. We conducted a pan-Canadian study to describe treatment differences and the incidence of emergency department visits (edvs), edvs leading to hospitalization (edvhs), and direct hospitalizations (hs) during adjuvant chemotherapy. Methods: The cohort consisted of women diagnosed with early-stage breast cancer (stages i-iii) during 2007-2012 in British Columbia, Manitoba, Ontario, or Nova Scotia who underwent curative surgery. Parallel provincial analyses were undertaken using linked clinical, registry, and administrative databases. The incidences of edvs, edvhs, and hs in the 6 months after treatment initiation were examined for patients treated with adjuvant chemotherapy. Results: The cohort consisted of 50,224 patients. The proportion of patients who received chemotherapy varied by province, with Ontario having the highest proportion (46.4%), and Nova Scotia, the lowest proportion (38.0%). Age, stage, receptor status, comorbidities, and geographic location were associated with receipt of chemotherapy in all provinces. Ontario had the highest proportion of patients experiencing an edv (36.1%), but the lowest proportion experiencing h (6.4%). Conversely, British Columbia had the lowest proportion of patients experiencing an edv (16.0%), but the highest proportion experiencing h (26.7%). The proportion of patients having an edvh was similar across provinces (13.9%-16.8%). Geographic location was associated with edvs, edvhs, and hs in all provinces. Conclusions: Intra- and inter-provincial differences in the use of chemotherapy and acute care were observed. Understanding variations in care can help to identify gaps and opportunities for improvement and shared learnings.


Subject(s)
Breast Neoplasms/therapy , Emergency Service, Hospital/statistics & numerical data , Hospitalization/statistics & numerical data , Aged , Canada , Chemotherapy, Adjuvant , Female , Humans , Middle Aged
4.
BMC Cancer ; 19(1): 42, 2019 Jan 09.
Article in English | MEDLINE | ID: mdl-30626375

ABSTRACT

BACKGROUND: In Canada, clinical practice guidelines recommend breast cancer screening, but there are gaps in adherence to recommendations for screening, particularly among certain hard-to-reach populations, that may differ by province. We compared stage of diagnosis, proportion of screen-detected breast cancers, and length of diagnostic interval for immigrant women versus long-term residents of BC and Ontario. METHODS: We conducted a retrospective cohort study using linked administrative databases in BC and Ontario. We identified all women residing in either province who were diagnosed with incident invasive breast cancer between 2007 and 2011, and determined who was foreign-born using the Immigration Refugee and Citizenship Canada database. We used descriptive statistics and bivariate analyses to describe the sample and study outcomes. We conducted multivariate analyses (modified Poisson regression and quantile regression) to control for potential confounders. RESULTS: There were 14,198 BC women and 46,952 Ontario women included in the study population, of which 11.8 and 11.7% were foreign-born respectively. In both provinces, immigrants and long-term residents had similar primary care access. In both provinces, immigrant women were significantly less likely to have a screen-detected breast cancer (adjusted relative risk 0.88 [0.79-0.96] in BC, 0.88 [0.84-0.93] in Ontario) and had a significantly longer median diagnostic interval (2 [0.2-3.8] days in BC, 5.5 [4.4-6.6] days in Ontario) than long-term residents. Women from East Asia and the Pacific were less likely to have a screen-detected cancer and had a longer diagnostic interval, but were diagnosed at an earlier stage than long-term residents. In Ontario, women from Latin America and the Caribbean and from South Asia were less likely to have a screen-detected cancer, had a longer median diagnostic interval, and were diagnosed at a later stage than long-term residents. These findings were not explained by access to primary care. CONCLUSIONS: There are inequalities in breast cancer diagnosis for Canadian immigrant women. We have identified particular immigrant groups (women from Latin America and the Caribbean and from South Asia) that appear to be subject to disparities in the diagnostic process that need to be addressed in order to effectively reduce gaps in care.


Subject(s)
Breast Neoplasms/diagnosis , Breast Neoplasms/ethnology , Emigrants and Immigrants , Aged , British Columbia/epidemiology , Cohort Studies , Databases, Factual , Ethnicity , Female , Humans , Incidence , Middle Aged , Neoplasm Staging , Ontario/epidemiology , Retrospective Studies
5.
Osteoporos Int ; 28(12): 3439-3449, 2017 12.
Article in English | MEDLINE | ID: mdl-28993862

ABSTRACT

Breast cancer survivors are at high osteoporosis risk. Bone mineral density testing plays a key role in osteoporosis management. We analyzed a historical utilization of bone mineral density testing in breast cancer survivors. The utilization remained low in the 1995-2008 period. Lower socio-economic status and rural residency were associated with lower utilization. INTRODUCTION: To evaluate the utilization of bone mineral density (BMD) testing for female breast cancer survivors aged 65+ surviving ≥ 3 years in British Columbia, Canada. METHODS: A retrospecitve population-based data linkage study. Trends in proportion of survivors with ≥ 1 BMD test for each calendar year from 1995 to 2008 were evaluated with a serial cross-sectional analysis. Associations between factors (socio-demographic and clinical) and BMD testing rates over the period 2006-2008 for 7625 survivors were evaluated with a cross-sectional analysis and estimated as adjusted prevalence ratios (PRadj) using log-binomial models. RESULTS: Proportions of survivors with ≥ 1 BMD test increased from 1.0% in 1995 to 10.1% in 2008. The BMD testing rate in 2006-2008 was 26.5%. Socio-economic status (SES) and urban/rural residence were associated with BMD testing rates in a dose-dependent relationship (p for trend< 0.01). Survivors with lower SES (PRadj = 0.66-0.78) or rural residence (PRadj = 0.70) were 20-30% less likely to have BMD tests, compared with survivors with the highest SES or urban residence. BMD testing rates were also negatively associated with older age (75+) (PRadj = 0.47; 95% CI = 0.42, 0.52), nursing home residency (0.05; 0.01, 0.39), recent osteoporotic fractures (0.21; 0.14, 0.32), and no previous BMD tests (0.26; 0.23, 0.29). CONCLUSION: Utilization of BMD testing was low for breast cancer survivors in BC, Canada. Lower SES and rural residence were associated with lower BMD testing rates. IMPLICATION FOR CANCER SURVIVORS: Female breast cancer survivors, especially those with lower SES or rural residence, should be encouraged to receive BMD tests as recommended by Canadian guidelines.


Subject(s)
Bone Density/physiology , Breast Neoplasms/physiopathology , Cancer Survivors/statistics & numerical data , Osteoporosis, Postmenopausal/diagnosis , Absorptiometry, Photon/statistics & numerical data , Aged , Breast Neoplasms/epidemiology , Breast Neoplasms/therapy , British Columbia/epidemiology , Cross-Sectional Studies , Female , Health Services Accessibility/statistics & numerical data , Humans , Osteoporosis, Postmenopausal/epidemiology , Retrospective Studies , Risk Assessment/methods , Rural Health/statistics & numerical data , Social Class
6.
Curr Oncol ; 24(2): 81-89, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28490921

ABSTRACT

INTRODUCTION: Oncologists have traditionally been responsible for providing routine follow-up care for cancer survivors; in recent years, however, primary care providers (pcps) are taking a greater role in care during the follow-up period. In the present study, we used a longitudinal multi-province retrospective cohort study to examine how primary care and specialist care intersect in the delivery of breast cancer follow-up care. METHODS: Various databases (registry, clinical, and administrative) were linked in each of four provinces: British Columbia, Manitoba, Ontario, and Nova Scotia. Population-based cohorts of breast cancer survivors were identified in each province. Physician visits were identified using billings or claims data and were classified as visits to primary care (total, breast cancer-specific, and other), oncology (medical oncology, radiation oncology, and surgery), and other specialties. The mean numbers of visits by physician type and specialty, or by combinations thereof, were examined. The mean numbers of visits for each follow-up year were also examined by physician type. RESULTS: The results showed that many women (>64%) in each province received care from both primary care and oncology providers during the follow-up period. The mean number of breast cancer-specific visits to primary care and visits to oncology declined with each follow-up year. Interprovincial variations were observed, with greater surgeon follow-up in Nova Scotia and greater primary care follow-up in British Columbia. Provincial differences could reflect variations in policies and recommendations, relevant initiatives, and resources or infrastructure to support pcp-led follow-up care. CONCLUSIONS: Optimizing the role of pcps in breast cancer follow-up care might require strategies to change attitudes about pcp-led follow-up and to better support pcps in providing survivorship care.

7.
Curr Oncol ; 24(2): 95-102, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28490923

ABSTRACT

BACKGROUND: Family physicians (fps) play a role in aspects of personalized medicine in cancer, including assessment of increased risk because of family history. Little is known about the potential role of fps in supporting cancer patients who undergo tumour gene expression profile (gep) testing. METHODS: We conducted a mixed-methods study with qualitative and quantitative components. Qualitative data from focus groups and interviews with fps and cancer specialists about the role of fps in breast cancer gep testing were obtained during studies conducted within the pan-Canadian canimpact research program. We determined the number of visits by breast cancer patients to a fp between the first medical oncology visit and the start of chemotherapy, a period when patients might be considering results of gep testing. RESULTS: The fps and cancer specialists felt that ordering gep tests and explaining the results was the role of the oncologist. A new fp role was identified relating to the fp-patient relationship: supporting patients in making adjuvant therapy decisions informed by gep tests by considering the patient's comorbid conditions, social situation, and preferences. Lack of fp knowledge and resources, and challenges in fp-oncologist communication were seen as significant barriers to that role. Between 28% and 38% of patients visited a fp between the first oncology visit and the start of chemotherapy. CONCLUSIONS: Our findings suggest an emerging role for fps in supporting patients who are making adjuvant treatment decisions after receiving the results of gep testing. For success in this new role, education and point-of-care tools, together with more effective communication strategies between fps and oncologists, are needed.

8.
Am J Epidemiol ; 186(7): 885-893, 2017 Oct 01.
Article in English | MEDLINE | ID: mdl-28535174

ABSTRACT

We undertook a re-analysis of the Canadian data from the 13-country case-control Interphone Study (2001-2004), in which researchers evaluated the associations of mobile phone use with the risks of brain, acoustic neuroma, and parotid gland tumors. In the main publication of the multinational Interphone Study, investigators concluded that biases and errors prevented a causal interpretation. We applied a probabilistic multiple-bias model to address possible biases simultaneously, using validation data from billing records and nonparticipant questionnaires as information on recall error and selective participation. In our modeling, we sought to adjust for these sources of uncertainty and to facilitate interpretation. For glioma, when comparing those in the highest quartile of use (>558 lifetime hours) to those who were not regular users, the odds ratio was 2.0 (95% confidence interval: 1.2, 3.4). After adjustment for selection and recall biases, the odds ratio was 2.2 (95% limits: 1.3, 4.1). There was little evidence of an increase in the risk of meningioma, acoustic neuroma, or parotid gland tumors in relation to mobile phone use. Adjustments for selection and recall biases did not materially affect interpretation in our results from Canadian data.


Subject(s)
Brain Neoplasms/etiology , Cell Phone , Glioma/etiology , Meningioma/etiology , Neuroma, Acoustic/etiology , Parotid Neoplasms/etiology , Adult , Bias , Brain Neoplasms/epidemiology , Canada , Case-Control Studies , Electromagnetic Fields/adverse effects , Female , Glioma/epidemiology , Humans , Logistic Models , Male , Meningeal Neoplasms/epidemiology , Meningeal Neoplasms/etiology , Middle Aged , Neuroma, Acoustic/epidemiology , Parotid Neoplasms/epidemiology , Risk Factors
10.
Blood Cancer J ; 2: e98, 2012 Dec 21.
Article in English | MEDLINE | ID: mdl-23262804

ABSTRACT

A previous US study reported poorer survival in children with acute lymphoblastic leukemia (ALL) exposed to extremely low-frequency magnetic fields (ELF-MF) above 0.3 µT, but based on small numbers. Data from 3073 cases of childhood ALL were pooled from prospective studies conducted in Canada, Denmark, Germany, Japan, UK and US to determine death or relapse up to 10 years from diagnosis. Adjusting for known prognostic factors, we calculated hazard ratios (HRs) and 95% confidence intervals (CI) for overall survival and event-free survival for ELF-MF exposure categories and by 0.1 µT increases. The HRs by 0.1 µT increases were 1.00 (CI, 0.93-1.07) for event-free survival analysis and 1.04 (CI, 0.97-1.11) for overall survival. ALL cases exposed to >0.3 µT did not have a poorer event-free survival (HR=0.76; CI, 0.44-1.33) or overall survival (HR=0.96; CI, 0.49-1.89). HRs varied little by subtype of ALL. In conclusion, ELF-MF exposure has no impact on the survival probability or risk of relapse in children with ALL.

11.
Allergy ; 63(9): 1156-63, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18699932

ABSTRACT

BACKGROUND: Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of receptors that bind sialic acid and mostly contain immunoreceptor tyrosine-based inhibitory motifs, suggesting that these molecules possess inhibitory functions. We have recently identified Siglec-8 as an eosinophil-prominent Siglec, and cross-linking of Siglec-8 on human eosinophils induces apoptosis. In this article, we address the in vivo consequences of Siglec engagement. We and others have identified mouse Siglec-F as the closest functional paralog of human Siglec-8, based on shared ligand-binding and expression pattern. We therefore hypothesized that Siglec-F engagement would affect levels and viability of eosinophils in vivo. METHODS: Wild type and hypereosinophilic mice were administered Siglec-F antibody and levels of eosinophils in peripheral blood and tissue were measured. Eosinophil apoptosis (in vivo and in vitro) was determined by binding of Annexin-V. RESULTS: Studies in IL-5 transgenic mice, displaying hypereosinophilia, show that administration of a single dose of Siglec-F antibody results in rapid reductions in quantum of eosinophils in the blood. This decrease was accompanied by reductions in tissue eosinophils. Quantum of eosinophils in blood was decreased using two separate antibodies, as well as in other mouse models (wild type mice and in a mouse model of chronic eosinophilic leukemia). Mechanistic studies demonstrated that Siglec-F antibody administration induced apoptosis of eosinophils in vivo and in vitro. CONCLUSION: These data demonstrate that activation of innate immune receptors, like Siglec-F, can significantly reduce mouse eosinophil viability. As such, targeting Siglec-8/F may be a therapeutic approach for eosinophilic disorders.


Subject(s)
Antibodies/pharmacology , Antigens, Differentiation, Myelomonocytic/metabolism , Apoptosis/immunology , Eosinophilia/blood , Animals , Eosinophilia/immunology , Eosinophils , Humans , Mice , Mice, Inbred BALB C , Sialic Acid Binding Immunoglobulin-like Lectins
12.
Eur J Cancer ; 44(6): 830-9, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18329873

ABSTRACT

PURPOSE: The aim of this study was to assess the risk of second malignant neoplasms (SMNs) other than central nervous system (CNS) neoplasms after childhood CNS cancer in an international multicentre study. METHODS: Individual data on cases of CNS cancer in children (0-14 years) and on subsequent SMNs were obtained from 13 population-based cancer registries contributing data for different time periods in 1943-2000. Standardised incidence ratios (SIRs) with 95% confidence intervals (CI), absolute excess risk and cumulative incidence of SMNs were computed. RESULTS: We observed 43 SMNs in 8431 CNS cancer survivors. The SIR was 10.6 (4.85-20.1) for thyroid cancer (nine cases), 2.75 (1.01-5.99) for leukaemia (six cases) and 2.47 (0.90-5.37) for lymphoma (six cases). The SIRs were highest in the first 10 years after CNS cancer diagnosis. The cumulative incidence of non-CNS SMNs was 3.30% (0.95-5.65%) within 45 years after a CNS cancer diagnosis. Within 15 years, the cumulative incidence was highest for cases diagnosed after 1980 (0.56%, 95% CI: 0.29-0.82%). CONCLUSION: This population-based study indicates that about one every 180 survivors of a childhood CNS cancer will develop a non-CNS SMN within the following 15 years. The excess is higher after glioma and embryonal malignant tumour than after another CNS tumour.


Subject(s)
Central Nervous System Neoplasms/epidemiology , Neoplasms, Second Primary/epidemiology , Adolescent , Adult , Aged , Child , Child, Preschool , Epidemiologic Methods , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Risk
13.
Br J Cancer ; 93(1): 159-66, 2005 Jul 11.
Article in English | MEDLINE | ID: mdl-15970927

ABSTRACT

An analysis of other primary cancers in individuals with non-Hodgkin's lymphoma (NHL) can help to elucidate this cancer aetiology. In all, 109 451 first primary NHL were included in a pooled analysis of 13 cancer registries. The observed numbers of second cancers were compared to the expected numbers derived from the age-, sex-, calendar period- and registry-specific incidence rates. We also calculated the standardised incidence ratios for NHL as a second primary after other cancers. There was a 47% (95% confidence interval 43-51%) overall increase in the risk of a primary cancer after NHL. A strongly significant (P<0.001) increase was observed for cancers of the lip, tongue, oropharynx*, stomach, small intestine, colon*, liver, nasal cavity*, lung, soft tissues*, skin melanoma*, nonmelanoma skin*, bladder*, kidney*, thyroid*, Hodgkin's lymphoma*, lymphoid leukaemia* and myeloid leukaemia. Non-Hodgkin's lymphoma as a second primary was increased after cancers marked with an asterisk. Patterns of risk indicate a treatment effect for lung, bladder, stomach, Hodgkin's lymphoma and myeloid leukaemia. Common risk factors may be involved for cancers of the lung, bladder, nasal cavity and for soft tissues, such as pesticides. Bidirectional effects for several cancer sites of potential viral origin argue strongly for a role for immune suppression in NHL.


Subject(s)
Lymphoma, Non-Hodgkin/complications , Neoplasms, Second Primary/epidemiology , Aged , Female , Humans , Male , Middle Aged , Neoplasms, Second Primary/complications
14.
Bioelectromagnetics ; 22(3): 161-9, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11255211

ABSTRACT

Study of the health effects of magnetic fields often depends on identifying determinants and hence indicators of personal exposure. This study identified determinants of children's exposure to magnetic fields and constructed a prediction model for them. For 632 children participating in a case-control study of childhood leukemia, we made direct measures of exposure over 48 h using a portable device, together with observations on candidate determinants. A child's age and sex, the proportion of time spent in the home, and their parents' education or income were very weak predictors of (logged) mean 48 h magnetic field (R(2) < 1%). More important were province (R(2) = 8.0%) and type of residence (R(2) = 11.3%). Low temperatures at the time of measurement were associated with high fields (about 20% increase for each 10 degrees C below 14, R(2) = 4.9%). Several visible attributes of wiring around residences predicted exposure, mostly captured in the Wertheimer-Leeper wire code (R(2) = 13.5%). Stationary 24 h measurement in the bedroom (R(2) = 63.3%) and spot measurements outside the house (R(2) = 40.7%) predicted personal exposures best. Adding other minor predictors increased only slightly variance explained by 24 h stationary (R(2) = 66.2%) and spot (R(2) = 46.8%) measurements. Without spot or stationary measurements, the best model was much less powerful (R(2) = 29.0%). We conclude that spot measurements outside the residence provide a moderately effective basis for estimating exposure for children living there, but do not perform as well as 24 h stationary measurements in the child's bedroom. Although several other easily-observed variables were associated with personal exposure, they were weak determinants, either individually or in combination.


Subject(s)
Electromagnetic Fields , Environmental Exposure , Leukemia/epidemiology , Adolescent , Canada/epidemiology , Case-Control Studies , Child , Educational Status , Electromagnetic Fields/adverse effects , Female , Housing , Humans , Income , Male , Microclimate , Multivariate Analysis , Parents , Temperature , Time Factors
15.
Article in English | MEDLINE | ID: mdl-11202059

ABSTRACT

Since the Royal Society of Canada report on potential health risks of radiofrequency (RF) fields from wireless telecommunications in the spring of 1999, there have been several newly published reports on risks associated with the use of mobile phones. This article provides a summary of scientific research on the potential health effects of radiofrequency fields that has been reported since the original Royal Society report was published. This update also discusses several earlier results not included in the original report.


Subject(s)
Electromagnetic Fields/adverse effects , Animals , Cell Physiological Phenomena/radiation effects , Congenital Abnormalities/epidemiology , Congenital Abnormalities/etiology , DNA Damage , Female , Hot Temperature/adverse effects , Humans , Male , Neoplasms/epidemiology , Neoplasms/etiology , Ornithine Decarboxylase/metabolism , Rats
17.
Scand J Work Environ Health ; 25(4): 368-75, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10505663

ABSTRACT

OBJECTIVES: This study sought to characterize personal exposures of Canadian children to 60-Hz magnetic and electric fields and explain the variability. METHODS: Altogether 382 Canadian children up to 15 years of age wore meters recording 60-Hz electric and magnetic fields over 2 days. Meter location was noted. Thereafter, meters measured fields in the center of the children's bedrooms for 24 hours. Personal exposures were calculated for home, school or day care, outside the home, bedroom at night, and all categories combined (total). RESULTS: The arithmetic mean (AM) was 0.121 microT [geometric mean (GM): 0.085 microT), range 0.01-0.8 microT] for total magnetic fields. Fifteen percent of the total exposures exceeded 0.2 microT. The AM of the total electric fields was 14.4 (GM 12.3, range 0.82-64.7) V/m. By location category, the highest and lowest magnetic fields occurred at home during the day (0.142 microT) and during the night (0.112 microT), respectively. Measurements during sleep provided the highest correlation with total magnetic field exposure. Province of measurement explained 14.7% of the variation in the logarithms of total magnetic fields, and season accounted for an additional 1.5%. CONCLUSIONS: This study has identified differences in children's magnetic field exposures between provinces. Measurements at night provided the best surrogate for predicting total magnetic field exposure, followed by at-home exposure and 24-hour bedroom measurements. Electrical heating and air conditioning, wiring type, and type of housing appear to be promising indicators of magnetic field levels.


Subject(s)
Electromagnetic Fields , Environmental Exposure , Canada , Child , Humans
18.
Am J Epidemiol ; 149(9): 831-42, 1999 May 01.
Article in English | MEDLINE | ID: mdl-10221320

ABSTRACT

In a case-control study of childhood leukemia in relation to exposure to power-frequency electric and magnetic fields (EMF), 399 children resident in five Canadian provinces who were diagnosed at ages 0-14 years between 1990 and 1994 (June 1995 in British Columbia and Quebec) were enrolled, along with 399 controls. Exposure assessment included 48-hour personal EMF measurement, wire coding and magnetic field measurements for subjects' residences from conception to diagnosis/reference date, and a 24-hour magnetic field bedroom measurement. Personal magnetic fields were not related to risk of leukemia (adjusted odds ratio (OR) = 0.95, p for trend = 0.73) or acute lymphatic leukemia (OR = 0.93, p for trend = 0.64). There were no clear associations with predicted magnetic field exposure 2 years before the diagnosis/reference date or over the subject's lifetime or with personal electric field exposure. A statistically nonsignificant elevated risk of acute lymphatic leukemia was observed with very high wiring configurations among residences of subjects 2 years before the diagnosis/reference date (OR = 1.72 compared with underground wiring, 95% confidence interval 0.54-5.45). These results provide little support for a relation between power-frequency EMF exposure and risk of childhood leukemia.


Subject(s)
Electromagnetic Fields/adverse effects , Leukemia/etiology , Adolescent , Canada/epidemiology , Case-Control Studies , Child , Child, Preschool , Epidemiologic Methods , Female , Humans , Infant , Leukemia/epidemiology , Male , Regression Analysis , Residence Characteristics , Risk Factors
19.
Can J Public Health ; 89 Suppl 1: S53-62, S58-68, 1998.
Article in English, French | MEDLINE | ID: mdl-9654794

ABSTRACT

This article reviews the available epidemiologic evidence for relationships between the development of cancer in childhood and environmental agents, specifically chemicals, ionizing radiation, low-frequency electromagnetic fields, and infectious agents. Chemical exposures include medications and other drugs, components of diet, and second-hand exposure to industrial chemicals and to environmental carcinogens. Ionizing radiation is the only well-established risk factor for childhood cancers. Suggestive associations with excess childhood cancer risk have been found with exposures to paints, petroleum products, solvents, pesticides and metals. An excess risk of brain tumours has been reported with ingestion of n-nitroso compounds, and there have been positive findings relating leukemia risk and infections. Studies of risk of childhood cancer with parental use of alcohol and with parental smoking have been generally negative, while the inconsistencies and generally low risks reported in studies of power-frequency electromagnetic fields do not support a causal relationship.


Subject(s)
Environmental Exposure/adverse effects , Environmental Pollutants/adverse effects , Neoplasms/etiology , Canada/epidemiology , Child , Female , Humans , Neoplasms/epidemiology , Pregnancy , Prenatal Exposure Delayed Effects , Risk Factors
20.
Clin Nurs Res ; 2(4): 396-410; discussion 411-3, 1993 Nov.
Article in English | MEDLINE | ID: mdl-8220195

ABSTRACT

This study examines the development of mothers' understanding of their infants' crying. Semistructured tape-recorded interviews were conducted with 17 mothers at 6 weeks, 10 weeks, and 16 weeks postpartum. The mothers (9 primiparous, 8 multiparous) were chosen for their good health status and for their immediate support system. Two major themes were identified from the interviews. In general, it was found that as the mothers became more experienced, the understanding of the cry situation became more complete and soothing was more effective. The relation between crying and soothing became more differentiated, more cohesive, and more complete. The effect of experience on understanding was particularly dramatic in the case of multiparous mothers. Both health promotional and illness prevention programming are proposed as nursing care measures for mothers of crying infants. The important assumptions underlying each approach are delineated.


Subject(s)
Communication , Crying , Infant Care , Mother-Child Relations , Mothers/psychology , Adaptation, Psychological , Cross-Sectional Studies , Female , Humans , Infant , Infant, Newborn , Longitudinal Studies , Parity , Surveys and Questionnaires
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