Birth characteristics and childhood carcinomas.

BACKGROUND: Carcinomas in children are rare and have not been well studied. METHODS: We conducted a population-based case-control study and examined associations between birth characteristics and childhood carcinomas diagnosed from 28 days to 14 years during 1980-2004 using pooled data from five states (NY, WA, MN, TX, and CA) that linked their birth and cancer registries. The pooled data set contained 57,966 controls and 475 carcinoma cases, including 159 thyroid and 126 malignant melanoma cases. We used unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: White compared with 'other' race was positively associated with melanoma (OR=3.22, 95% CI 1.33-8.33). Older maternal age increased the risk for melanoma (OR(per 5-year age increase)=1.20, 95% CI 1.00-1.44), whereas paternal age increased the risk for any carcinoma (OR=1.10(per 5-year age increase), 95% CI 1.01-1.20) and thyroid carcinoma (OR(per 5-year age increase)=1.16, 95% CI 1.01-1.33). Gestational age < 37 vs 37-42 weeks increased the risk for thyroid carcinoma (OR=1.87, 95% CI 1.07-3.27). Plurality, birth weight, and birth order were not significantly associated with childhood carcinomas. CONCLUSION: This exploratory study indicates that some birth characteristics including older parental age and low gestational age may be related to childhood carcinoma aetiology.

Maternal vitamin and iron supplementation and risk of infant leukaemia: a report from the Children's Oncology Group.

BACKGROUND: Prenatal supplementation has been inversely associated with childhood, but not with infant, leukaemia. METHODS: Mothers of 443 cases of infant leukaemia diagnosed during 1996-2006 and 324 frequency-matched controls completed interviews. Associations were evaluated by unconditional logistic regression. RESULTS: We observed no associations between prenatal vitamin (odds ratio (OR)=0.79, 95% confidence interval (CI): 0.44-1.42) or iron supplementation (OR=1.07, 95% CI: 0.75-1.52) and infant leukaemia after adjustment for race/ethnicity and income. Similar results were observed for leukaemia subtypes analysed separately. CONCLUSION: The observed null associations may be attributable to high supplementation rates and/or national fortification programmes.

Parental educational attainment as an indicator of socioeconomic status and risk of childhood cancers.

BACKGROUND: Little has been reported on socioeconomic (SES) patterns of risk for most forms of childhood cancer. METHODS: Population-based case-control data from epidemiological studies of childhood cancer conducted in five US states were pooled and associations of maternal, paternal and household educational attainment with childhood cancers were analysed. Odds ratios (ORs) and 95% confidence intervals were estimated using logistic regression, controlling for confounders. RESULTS: Although there was no association with parental education for the majority of cancers evaluated, there was an indication of a positive association with lower education for Hodgkin's and Burkitt's lymphoma and Wilm's tumour, with the ORs ranging from 1.5 to >3.0 times that of more educated parents. A possible protective effect was seen for lower parental education and astrocytoma and hepatoblastoma, with ORs reduced by 30 to 40%. CONCLUSIONS: These study results should be viewed as exploratory because of the broad nature of the SES assessment, but they give some indication that childhood cancer studies might benefit from a more thorough assessment of SES.

Birth characteristics and the risk of childhood rhabdomyosarcoma based on histological subtype.

BACKGROUND: Little is known about risk factors for childhood rhabdomyosarcoma (RMS) and the histology-specific details are rare. METHODS: Case-control studies formed by linking cancer and birth registries of California, Minnesota, New York, Texas and Washington, which included 583 RMS cases (363 embryonal and 85 alveolar RMS) and 57 966 randomly selected control subjects, were analysed using logistic regression. The associations of RMS (overall, and based on embryonal or alveolar histology) with birth weight across five 500 g categories (from 2000 to 4500 g) were examined using normal birth weight (2500-3999 g) as a reference. Large (>90th percentile) and small (<10th percentile) size for gestational age were calculated based on birth weight distributions in controls and were similarly examined. RESULTS: High birth weight increased the risk of embryonal RMS and RMS overall. Each 500 g increase in birth weight increased the risk of embryonal RMS (odds ratio (OR)=1.27, 95% confidence interval (CI)=1.14-1.42) and RMS overall (OR=1.18, 95% CI=1.09-1.29). Large size for gestational age also significantly increased the risk of embryonal RMS (OR=1.42, 95% CI=1.03-1.96). CONCLUSIONS: These data suggest a positive association between accelerated in utero growth and embryonal RMS, but not alveolar RMS. These results warrant cautious interpretation owing to the small number of alveolar RMS cases.

Perinatal risk factors for hepatoblastoma.

We confirmed the strong association of hepatoblastoma with very low birth weight (relative risk <1000 g vs >or=2000 g=25.6; 95% confidence interval: 7.70-85.0) and demonstrated independent associations with congenital abnormalities and maternal Asian race in a population-based Minnesota study that included 36 cases and 7788 controls.

A comparison of the effects of imposed extension and flexion movements on Parkinsonian rigidity.

OBJECTIVE: To test a hypothesis that Parkinsonian rigidity is more pronounced in imposed extension than flexion movement. METHODS: Twelve Parkinsonian subjects (both "Off" and "On" medication states) and seven control subjects participated in the protocol, in which a servomotor imposed wrist flexion and extension. Rigidity was quantitatively evaluated by the rectified torque integral with time, i.e., temporal score, and by the torque integral with joint angle, i.e., work score, for extension and flexion, respectively. RESULTS: In the "Off" state, the imposed extension induced a significantly higher resistance than did flexion. Dopaminergic medication significantly reduced the temporal score associated with imposed extension, and significantly decreased the work score of both movements. Compared with controls, the scores were higher for patients in the "On" state. CONCLUSIONS: Rigidity is more readily elicited in extension movement. The distinction is not evident in clinical practice, whereas it can be clearly revealed with the application of biomechanical analyses. SIGNIFICANCE: This distinction may prove to be a standard feature of rigidity. The procedures may be helpful in diagnosis and useful in evaluating new treatments and developing rehabilitation programs.