Birth weight and melanoma risk: a population-based case-control study

Childhood Body Size and the Risk of Malignant Melanoma in Adulthood

Malignant melanoma (MM) is the most aggressive form of skin cancer. Adult anthropometry influences MM development; however, associations between childhood body size and future melanomagenesis are largely unknown. We investigated whether height, body mass index (BMI; weight (kg)/height (m)²), and body surface area (BSA) at ages 7–13 years and birth weight are associated with adult MM. Data from the Copenhagen School Health Records Register, containing annual height and weight measurements of 372,636 Danish children born in 1930–1989, were linked with the Danish Cancer Registry. Cox regression analyses were performed. During follow-up, 2,329 MM cases occurred. Height at ages 7–13 years was significantly associated with MM, even after BMI and BSA adjustments. No significant BMI-MM or BSA-MM associations were detected when adjusting for height. Children who were persistently tall at both age 7 years and age 13 years had a significantly increased MM risk compared with children who grew taller between those ages. Birth weight was positively associated with MM. We conclude that associations between body size and MM originate early in life and are driven largely by height and birth weight, without any comparable influence of BMI or BSA. Melanoma transformation is unlikely to be due to height per se; however, height-regulating processes in childhood present new areas for mechanistic explorations of this disease.

Birth weight and adult cancer incidence: large prospective study and meta-analysis

BACKGROUND

Most evidence about associations between birth weight and adult cancer risk comes from studies linking birth records to cancer registration data, where information on known risk factors for cancer is generally lacking. Here, we report on associations between birth weight and cause-specific cancer risk in a large cohort of UK women, and investigate how observed associations are affected by other factors.

METHODS

A total of 453 023 women, born in the 1930s and 1940s, reported their birth weight, maternal smoking, parental heights, age at menarche, adult height, adult smoking, and many other personal characteristics. They were followed for incident cancer. Using Cox regression, relative risks by birth weight were estimated for cancers with more than 1500 incident cases, adjusting for 17 potential confounding factors, individually and simultaneously.

RESULTS

Birth weight reported in adulthood was strongly correlated with that recorded at birth (correlation coefficient = 0.78, P < 0.0001). Reported birth weight was associated with most of the potential confounding factors examined, the strongest association being with adult height. After 9.2 years follow-up per woman, 39 060 incident cancers were registered (4414 colorectal, 3175 lung, 1795 malignant melanoma, 14 542 breast, 2623 endometrial, 2009 ovarian, 1565 non-Hodgkin lymphoma, and 8937 other cancers). Associations with birth weight were null or weak and reduced after adjustment by adult height (P[trend] > 0.01 for every cancer, after adjustment). In contrast, adult height was strongly related to the risk of every cancer except lung cancer, after adjusting for birth weight and other factors (P[trend] < 0.0001 for most cancers). For lung cancer, adjusting for smoking reduced the association with birth weight. Meta-analyses were dominated by our findings.

CONCLUSION

Birth weight and adult height are correlated and likely to be markers of some aspect of growth that affects cancer risk in adulthood. However, birth weight adds little, if any, additional information to adult height as a predictor of cancer incidence in women.

Season of birth and other perinatal risk factors for melanoma

BACKGROUND

Ultraviolet radiation (UVR) exposure is the main risk factor for cutaneous malignant melanoma (CMM), but its specific effect in infancy is unknown. We examined whether season of birth, a proxy for solar UVR exposure in the first few months of life, is associated with CMM in childhood through young adulthood.

METHODS

National cohort study of 3,571,574 persons born in Sweden in 1973-2008, followed up for CMM incidence through 2009 (maximum age 37 years) to examine season of birth and other perinatal factors.

RESULTS

There were 1595 CMM cases in 63.9 million person-years of follow-up. We found a sinusoidal pattern in CMM risk by season of birth (P=0.006), with peak risk corresponding to birthdates in spring (March-May). Adjusted odds ratios for CMM by season of birth were 1.21 [95% confidence interval (CI), 1.05-1.39; P=0.008] for spring, 1.07 (95% CI, 0.92-1.24; P=0.40) for summer and 1.12 (95% CI, 0.96-1.29; P=0.14) for winter, relative to fall. Spring birth was associated with superficial spreading subtype of CMM (P=0.02), whereas there was no seasonal association with nodular subtype (P=0.26). Other CMM risk factors included family history of CMM in a sibling (>6-fold) or parent (>3-fold), female gender, high fetal growth and high paternal education level.

CONCLUSIONS

In this large cohort study, persons born in spring had increased risk of CMM in childhood through young adulthood, suggesting that the first few months of life may be a critical period of UVR susceptibility. Sun avoidance in early infancy may play an important role in the prevention of CMM in high-risk populations.

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.