Does ovary removal increase colorectal cancer risk?

May 25, 2016

Do sex hormone level changes from ovary removal increase colorectal cancer risk? Plus: The CDC releases the newest information on the birth rate among teenagers. Also, a look at the impact of hyperglycemia and excessive weight gain on offspring.

Women who have had their ovaries removed may be at increased risk of colorectal cancer as a result of alteration in sex hormone levels, according to a population analysis in British Journal of Surgery.

Researchers assessed data from women who had undergone oophorectomy between 1965 and 2011, identified through the Swedish Patient Registry. Standard incidence rations (SIRs) and 95% confidence intervals (CIs) were calculated and then compared to the general population. Stratification was used for unilateral and bilateral oophorectomy as well as hysterectomy without specification of whether the ovaries had been removed.

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During the study period, 195,973 women underwent oophorectomy and 3150 women (1.6%) were subsequently diagnosed with colorectal cancer (median follow-up: 18 years). Among the oophorectomized women, risk of colorectal cancer was increased compared with the general population (SIR: 1.30. 95% CI 1.26-1.35). Risk was lower in women who were younger at the age of oophorectomy (15–39 years: SIR: 1.10, 95% CI 0.97 to 1.23; 40–49 years: SIR 1.26, 95% CI 1.19 to 1.33; P for trend < 0.001). The highest risk period was 1 to 4 years following oophorectomy (SIR: 1.66, 95% CI 1.51 to 1.81; P<0.001).

Following multivariate analysis, women who underwent a bilateral oophorectomy seemed to have a higher risk of colorectal cancer than women who had a unilateral procedure (hazard ratio 2.28, 95% CI 1.33 to 3.91).

The researchers concluded that there appeared to be an increased risk of colorectal cancer following oophorectomy which was performed for benign indications.

NEXT: CDC's report on the teenaged birth rate


CDC: Teen birth rate in decline

The teenaged birth rate has reached a historic low, according to a recent report from the Centers for Disease Control and Prevention. In adolescent girls aged 15 to 19 years, the rate declined by 61% from 1991 to 2014, going from 61.8 births per 1000 to 24.2 births per 1000. However, the birth rate remained roughly twice as high for Hispanic and non-Hispanic black teenagers.

During the most recent years studied, 2006 to 2014, the teenaged birth rate declined 41% from 41.1 per 1000 to 24.2 per 1000. During that time, the largest declines were seen among Hispanic adolescents (51% from 77.4 to 38.0) and blacks (44%, from 61.9 to 34.9). Among white teenagers, the birth rate declined 35%, from 26.7 to 17.3.

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An analysis of data from 2013-2014 highlights the racial/ethnic disparities in births to teenagers in individual states. In New Jersey, the birth rate was 4.8, well below the national rate, but the birth rates for black teenagers and for Hispanics were 27.4 and 31.3, respectively. While the birth rate among black and non-Hispanic teenagers in New Jersey was below the nationwide average, it was still significantly higher than the white adolescent birth rate. In other states, such as Nebraska, birth rates approached the national average in white teenagers (16.2) but were well above the average among black teenagers (42.6) and Hispanic teenagers (53.9).  In other states, the disparities were much smaller but the birth rates were high across all populations; an example is Arkansas, where the birth rates were 37.7 for whites, 54.6 for blacks, and 46.5 for Hispanics.

The investigators highlighted some limitations to the report’s data. The estimates of teenaged birth rates for some racial/ethnic groups, such as American Indian/Alaskan Natives and Asian Pacific Islanders in all states, were not available at the state and/or county level because of small population size. The report also did not look at subgroups within ethnic groups, such as Mexican, Puerto Rican, and Cuban individuals in the Hispanic population.

NEXT: Hyperglycemia and excessive weight gain linked to childhood obesity


Hyperglycemia, excessive weight gain in pregnancy linked to childhood obesity

Children whose mothers have hyperglycemia and gain an excessive amount of weight during pregnancy are at increased risk of obesity during the first decade of life, according to results from a study by researchers from Kaiser Permanente. The findings were published in Maternal and Child Health Journal.

The authors assessed a population of 24,141 mothers and their offspring who were born at normal weight between 1995 and 2003. The 11,103 mothers had undergone screening for gestational diabetes mellitus (GDM) with a 50-g glucose challenge test (GCT) and a 3-hour 100-g oral glucose tolerance test if they were GCT-positive. Their 13,037 full-term offspring, who had normal birthweight, had their height and weight measured annually between ages 2 and 10 years to calculate gender-specific body mass index (BMI) percentiles using United States norms.

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The researchers found a significant trend toward development of childhood overweight (>85th percentile) and obesity (>95th percentile) during the first decade of life in children whose mothers had hyperglycemia (normal GCT, GCT-positive but no GDM, GDM) and a gestational weight gain >40 lb (P<0.0001 for both trends). The effects were sustained even after adjustment for potential confounders including maternal age, parity, and pre-pregnancy BMI.

The attributable risk for childhood obesity, the authors calculated, was 28.5% (95% confidence interval [CI] 15.9-41.1) for GDM and 16.4% (95% CI 9.2-23.2) for excessive gestational weight gain. “Both maternal hyperglycemia and excessive weight gain have independent effects to increase childhood obesity risks,” they said, urging research focused on prevention during pregnancy as a way to reduce childhood obesity.