Hormonal contraceptive use before and after conception in relation to preterm birth and small for gestational age: an observational cohort study.

OBJECTIVE: To evaluate whether hormonal contraceptives, used before or in early pregnancy, confer increased risk of preterm birth or reduced fetal growth. DESIGN: Population-based cohort study conducted by the Norwegian Institute of Public Health (Mother and Child Cohort Study, 1998-2008) with linkage to the Norwegian Prescription Registry and to the Medical Birth Registry of Norway. SETTING: Norway. POPULATION: Of the 48,615 pregnancies meeting study inclusion criteria, 44,734 pregnancies were included in the complete case analysis. METHODS: We characterised hormonal contraception by type (combination oral, progestin-only oral, vaginal ring, transdermal, and injectable) and specific progestin component. We used generalised estimating equations to estimate the odds of adverse outcome according to formulation used. Several sensitivity analyses were conducted. MAIN OUTCOME MEASURES: Preterm birth, small for gestational age. RESULTS: We observed a positive association between use of a combination oral contraceptive and preterm birth for all exposure periods (e.g. adjusted odds ratio 1.21, 95% confidence interval 1.04-1.41 for last use 12 to >4 months before conception); combination contraceptives containing the progestin norethisterone were consistently related to risk. Other types of hormonal contraception were generally not associated with preterm birth; none were related to small for gestational age. Observed associations were robust to sensitivity analyses. CONCLUSION: Hormonally active agents may exert dose-, agent-, and timing-specific effects on growth and development. We found that the particular progestin component is important when assessing the potential for adverse effects among former users of hormonal contraceptives.

Maternal hormonal contraceptive use and offspring overweight or obesity.

BACKGROUND/OBJECTIVES: Experiments in animal models have shown a positive association between in utero exposure to pharmacologic sex hormones and offspring obesity. The developmental effects of such hormones on human obesity are unknown. SUBJECTS/METHODS: Using data from a large, prospective pregnancy cohort study (n=19 652), with linkage to a national prescription registry, we evaluated the association between use of hormonal contraceptives before and after conception (defined from dispensed prescription data and characterized by last date of use relative to conception, 12 to >4 months before (n=3392), 4 to >1 months before (n=2541), 1 to >0 months before (n=2997) and 0-12 weeks after (n=567)) in relation to offspring overweight or obesity at age 3 years. RESULTS: We observed a weak, inverse association between early pregnancy use of a combination oral contraceptive and offspring overweight or obesity at age 3 (adjusted odds ratio (OR): 0.75, 95% confidence interval (CI): 0.53, 1.08) and a positive, but imprecise, association with use of a progestin-only oral contraceptive in early pregnancy (adjusted OR: 1.26, 95% CI: 0.79, 2.02). In general, no association was observed between the use of a hormonal contraceptive before conception and offspring overweight or obesity. A sensitivity analysis comparing combination oral contraceptive users in early pregnancy to other unplanned pregnancies without hormonal contraceptive use further strengthened the inverse association (adjusted OR: 0.70, 95% CI: 0.48, 1.02). Other sensitivity analyses were conducted to evaluate the robustness of the associations observed given varying assumptions. CONCLUSIONS: Pharmacologic sex hormones in early pregnancy may be inversely or positively associated with offspring overweight or obesity at age 3, depending on the specific formulation used. The present study provides support for the potential for environmental sources of hormonally active agents to exert developmental effects.

Physical activity and maternal-fetal circulation measured by Doppler ultrasound.

OBJECTIVE: To examine the association of physical activity on maternal-fetal circulation measured by uterine and umbilical artery Doppler flow velocimetry waveforms. STUDY DESIGN: Participants included 781 pregnant women with Doppler ultrasounds of the uterine and umbilical artery and who self-reported past week physical activity. Linear and generalized estimating equation regression models were used to examine these associations. RESULT: Moderate-to-vigorous total and recreational activity were associated with higher uterine artery pulsatility index (PI) and an increased risk of uterine artery notching as compared with reporting no total or recreational physical activity, respectively. Moderate-to-vigorous work activity was associated with lower uterine artery PI and a reduced risk of uterine artery notching as compared with no work activity. No associations were identified with the umbilical circulation measured by the resistance index. CONCLUSION: In this epidemiologic study, recreational and work activity were associated with opposite effects on uterine artery PI and uterine artery notching, although associations were modest in magnitude.

Gestational weight gain and predicted changes in offspring anthropometrics between early infancy and 3 years.

OBJECTIVE: To determine how gestational weight gain (GWG), categorized using the 2009 Institute of Medicine recommendations, relates to changes in offspring weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length z-scores (WLZ) between early infancy and 3 years. METHODS: Women with singleton infants were recruited from the third cohort of the Pregnancy, Infection, and Nutrition Study (2001-2005). Term infants with at least one weight or length measurement during the study period were included (n = 476). Multivariable linear mixed effects regression models estimated longitudinal changes in WAZ, LAZ and WLZ associated with GWG. RESULTS: In early infancy, compared with infants of women with adequate weight gain, those of women with excessive weight gains had higher WAZ, LAZ and WLZ. Excessive GWG ≥ 200% of the recommended amount was associated with faster rates of change in WAZ and LAZ and noticeably higher predicted mean WAZ and WLZ that persisted across the study period. CONCLUSIONS: GWG is associated with significant differences in offspring anthropometrics in early infancy that persisted to 3 years of age. More longitudinal studies that utilize maternal and paediatric body composition measures are necessary to understand the nature of this association.

Occupational exposure assessment in case-control studies: opportunities for improvement.

Community based case-control studies are an efficient means to study disease aetiologies, and may be the only practical means to investigate rare diseases. However, exposure assessment remains problematic. We review the literature on the validity and reliability of common case-control exposure assessment methods: occupational histories, job-exposure matrices (JEMs), self reported exposures, and expert assessments. Given the variable quality of current exposure assessment techniques, we suggest methods to improve assessments, including the incorporation of hygiene measurements: using data from administrative exposure databases; using results of studies identifying determinants of exposure to develop questionnaires; and where reasonable given latency and biological half life considerations, directly measuring exposures of study subjects.

Environmental contaminants as etiologic factors for diabetes.

For both type 1 and type 2 diabetes mellitus, the rates have been increasing in the United States and elsewhere; rates vary widely by country, and genetic factors account for less than half of new cases. These observations suggest environmental factors cause both type 1 and type 2 diabetes. Occupational exposures have been associated with increased risk of diabetes. In addition, recent data suggest that toxic substances in the environment, other than infectious agents or exposures that stimulate an immune response, are associated with the occurrence of these diseases. We reviewed the epidemiologic data that addressed whether environmental contaminants might cause type 1 or type 2 diabetes. For type 1 diabetes, higher intake of nitrates, nitrites, and N-nitroso compounds, as well as higher serum levels of polychlorinated biphenyls have been associated with increased risk. Overall, however, the data were limited or inconsistent. With respect to type 2 diabetes, data on arsenic and 2,3,7,8-tetrachlorodibenzo-p-dioxin relative to risk were suggestive of a direct association but were inconclusive. The occupational data suggested that more data on exposure to N-nitroso compounds, arsenic, dioxins, talc, and straight oil machining fluids in relation to diabetes would be useful. Although environmental factors other than contaminants may account for the majority of type 1 and type 2 diabetes, the etiologic role of several contaminants and occupational exposures deserves further study.

Comparison of assessment methods for pesticide exposure in a case-control interview study.

In epidemiologic studies, much of the variation in disease risk estimates associated with occupational pesticide exposure may be due to variation in exposure classification. The authors compared five different methods of using interview information to assess occupational pesticide exposure in a US-Canada case-control study of neuroblastoma (1992-1994). For each method, exposure assignment was compared with that of a reference method, and neuroblastoma effect estimates were calculated. Compared with the reference method, which included a complete review of occupation, industry, job tasks, and exposure-specific activities, the use of occupation-industry groups alone or in combination with general job task information diluted the exposed group by including individuals who were unlikely to have been truly exposed. The effect estimates representing associations between each exposure method and neuroblastoma were different enough to influence the study's conclusions, especially when the exposure was rare (for maternal occupational pesticide exposure, the odds ratio was 0.7 using the reference exposure assessment method and 3.2 using the occupation-industry group exposure assessment method). Exposure-specific questions about work activities can help investigators distinguish truly exposed individuals from those who report exposure but are unlikely to have been exposed above background levels and from those who have not been exposed but are misclassified as exposed because of their employment in an occupation-industry group determined a priori to be exposed.

Residential pesticide exposure and neuroblastoma.

Neuroblastoma is the most common neoplasm in children under 1 year of age. We examined the relation between residential exposure to pesticides and neuroblastoma, using data from a case-control study of risk factors for neuroblastoma. Incident cases of neuroblastoma (N = 538) were identified through the Pediatric Oncology Group and the Children's Cancer Group. One age-matched control was identified for each case by random digit dialing. Telephone interviews with each parent collected information on residential exposure to pesticides. Pesticide use in both the home and garden were modestly associated with neuroblastoma [odds ratio (OR) = 1.6 (95% confidence interval [95% CI] = 1.0-2.3, and OR = 1.7 (95% CI = 0.9-2.1), respectively]. Compared with infants [OR = 1.0 (95% CI = 0.6-2.0)], stronger associations were found for garden pesticides in children diagnosed after 1 year of age [OR = 2.2 (95% CI = 1.3-3.6)], which suggests that pesticides may act through a mechanism more common for neuroblastomas in older children. There was no evidence of differential pesticide effects in subgroups of neuroblastoma defined by MYCN oncogene amplification or tumor stage.

Collecting and using aboriginal health information in New South Wales.

OBJECTIVE: To describe the development of guidelines for the management of Aboriginal health information in NSW. The purpose of the guidelines is to promote the ethical management of Aboriginal health information, with appropriate consideration for cultural factors. METHODS: The guidelines were developed collaboratively by the NSW Aboriginal Health Partnership, which comprises NSW Health (the central administrative office, named NSW Department of Health, and the Area Health Services) and the NSW Aboriginal Health and Medical Research Council (AHMRC), the peak body representing member Aboriginal Community Controlled Health Services in NSW. A lengthy and comprehensive consultation process enabled a wide range of interested groups to have input into the guidelines. RESULTS: The project culminated in the production of the NSW Aboriginal Health Information Guidelines, covering the collection, ownership, storage, security, release, usage, interpretation and reporting of information, as well as issues of privacy and confidentiality. The Guidelines formed the basis of a formal Memorandum of Understanding, signed by the NSW Minister for Health, NSW Department of Health and the AHMRC, on 24 August 1998. CONCLUSIONS AND IMPLICATIONS: The Guidelines make an important contribution to meeting a need for protocols on the collection, ownership and use of Aboriginal health information. Their production reflects successful collaboration between government and Aboriginal Community Controlled Health Services in NSW. Future reviews of the Guidelines will ensure their effectiveness and consistency with Aboriginal community principles.

Jockey injuries in the United States.

CONTEXT: In the sport of horse racing, the position of the jockey and speed of the horse predispose the jockey to risk of injury. OBJECTIVE: To estimate rates of medically treated injuries among professional jockeys and identify patterns of injury events. DESIGN: Cross-sectional survey from data compiled by an insurance broker. Information on the cause of injury, location on the track, and body part injured was evaluated. SETTING: Official races at US professional racing facilities (n = 114) from January 1, 1993, through December 31, 1996. PARTICIPANTS: A licensed jockey population of approximately 2700 persons. MAIN OUTCOME MEASURES: Annual injury incidence rates per 1000 jockey-years, as well as injury type, cause, and location on the track. RESULTS: A total of 6545 injury events occurred during official races between 1993 and 1996 (606 per 1000 jockey-years). Nearly 1 in 5 injuries (18.8%) was to the jockey's head or neck. Other frequent sites included the leg (15.5%), foot/ankle (10.7%), back (10.7%), arm/hand (11.0%), and shoulder (9.6%). The most frequent location where injuries occurred was entering, within, or leaving the starting gate (35.1%), including 29.5% of head injuries, 39.8% of arm/hand injuries, and 52.0% of injuries to the leg/foot. Most head injuries resulted from being thrown from the horse (41.8%) or struck by the horse's head (23.2%). Being thrown from the horse was the cause of 55.1% of back and 49.6% of chest injuries. CONCLUSIONS: Our data suggest that jockeys have a high injury rate. Efforts are needed to reduce the number of potential injury events on the track and to improve protective equipment so events do not lead to injury.

Pesticides and childhood cancers.

To evaluate the possible association between pesticides and the risk of childhood cancers, epidemiologic studies published between 1970 and 1996 were critically reviewed. Thirty-one studies investigated whether occupational or residential exposure to pesticides by either parents or children was related to increased risk of childhood cancer. In general, the reported relative risk estimates were modest. Risk estimates appeared to be stronger when pesticide exposure was measured in more detail. Frequent occupational exposure to pesticides or home pesticide use was more strongly associated with both childhood leukemia and brain cancer than either professional exterminations or the use of garden pesticides. Occupational pesticide exposure was also associated with increased risk of Wilms' tumor, Ewing's sarcoma, and germ cell tumors. Residence on a farm, a proxy for pesticide exposure, was associated with increased risk of a number of childhood cancers. Although increased risk of some childhood cancers in association with pesticide exposure is suggested by multiple studies, methodological limitations common to many studies restrict conclusions; these include indirect exposure classification, small sample size, and potential biases in control selection. Opportunities for methodologic improvement in future studies of pesticides and childhood cancers are described.

Cervical kyphosis in patients who have Larsen syndrome.

Four patients who had Larsen syndrome and cervical kyphosis were managed operatively and followed for an average of seventy months (range, forty to ninety-two months). The preoperative cervical kyphosis ranged from 35 to 65 degrees. The patients had had a posterior cervical arthrodesis alone when they were infants, at an average age fo fourteen months (range, ten to sixteen months). In three infants, the kyphosis either stabilized (one patient) or reversed into lordosis (two patients). Thus, the kyphosis corrected gradually by continued anterior growth in the presence of a solid posterior fusion. In the fourth infant, the kyphosis progressed to 110 degrees because of pseudarthrosis. This child had anterior decompression and arthrodesis for an acute neurological deficit. We believe that cervical kyphosis is sometimes present but not diagnosed in patients who have Larsen syndrome. Early diagnosis followed by operative stabilization should help such patients avoid neurological deficits. Posterior cervical arthrodesis alone, performed in infancy, provided stability and the opportunity for the gradual correction of the deformity by continued anterior growth in three of our four patients.

Effect of joint position and ligament tension on the MR signal intensity of the cruciate ligaments of the knee.

Six cadaveric lower extremities were imaged with T1-weighted spin-echo pulse sequences with the knees extended and flexed to 90 degrees. Magnetic resonance signal intensities of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were compared. Changing from extension to flexion resulted in decreased signal intensity in six of six ACLs and five of six PCLs. Two of the knees were then imaged with and without tension applied to the ACL. Both specimens showed a decrease in signal intensity with tension, followed by an increase in signal intensity with release of the tension. Finally, in three of the limbs the ACL was surgically reconstructed and then imaged with and without tension applied to the tendon graft. Signal intensity decreased with tension and increased with release of the tension in all three specimens. Thus, joint position and changes in ligament tension affect the signal intensity of the ACL and PCL, generally resulting in a signal intensity decrease with tension.

The effects of a multicomponent smoking cessation program with chronic obstructive pulmonary disease outpatients.

While a number of multicomponent treatments have been utilized to control smoking, many of these are not suitable for some populations such as chronic obstructive pulmonary disease (COPD) patients because they consist of aversion procedures which can stress the body's cardiovascular system. Little research has been published regarding nonaversive approaches to smoking control in a COPD patient population. This study examined the long-term effects of a nonaversive multicomponent smoking cessation program consisting of brand fading and stimulus control with a COPD outpatient population as measured by self-report. Using four COPD outpatients, this study employed a multiple baseline design across subjects for a visual analysis of treatment effects. At 3- and 6-month follow-up, one subject had quit smoking. Two subjects who continued to smoke reduced their smoking frequency and drastically reduced their nicotine intake by brand fading to a cigarette containing lower amounts of nicotine. A fourth subject returned to her original brand of cigarettes, although she reduced her smoking frequency. Collaborators and measurements of thiocyanate levels were used as reliability checks on subjects' self-report.

A comparison of testicular tumors in black and white patients.

Testicular tumors are uncommon in black compared to white patients but several reports have indicated that this disease is more lethal in black patients. We reviewed the records of 840 post-puberal patients with primary tumors of the testis seen between 1949 and 1979. There were 17 black and 823 white patients. The predominant tumor in both groups of patients was seminmona. Ten black (58.5 per cent) and 329 white patients (29 per cent) had a non-seminomatous germ cell testicular tumor, while 494 white patients (60 per cent) had such a tumor. These observations alone suggest an over-all better prognosis in black than in white patients. The data demonstrate again the rarity of this disease black patients but our survey shows that black patients with testicular tumors have a better prognosis than has been reported previously.

Clinical examination of the head and neck.

In the head and neck examination portion of the ADA health screening program approximately 6% of the examinees were found to have at least one abnormality. Three patients had lesions that were highly suspected of being malignant. Most of the examinees were unaware of their condition, but a small percentage were aware and had chosen to have no diagnostic or curative procedures initiated. Three patients had manifestations of systemic disease of which they were unaware. A method of doing a head and neck examination was demonstrated to the dentists, and the finding of 6% of the dentists with some abnormality indicates the significance of the head and neck examination.