Memory Loss Linked to Sleep Apnea

Author: Allie Montgomery

As we get older, we expect a certain amount of memory loss, but this can be compounded if suffering from sleep apnea. A recent study, conducted by the University of California, shows that people who suffer from sleep apnea show tissue loss in the part of the brain that helps store memory.

The principal investigator for the study, Ronald Harper, a professor of neurobiology at the David Geffen School of Medicine at UCLA has stated that the study findings "demonstrate that impaired breathing during sleep can lead to serious brain injury that disrupts memory and thinking." Patients that suffer from sleep apnea stop breathing during the night and wake up repeatedly, leading to chronic daytime fatigue and concentration and memory difficulties. Research has also linked this condition to an increased risk of heart disease, diabetes, and stroke.

In this study, the team used MRI to scan the brains of the patients with sleep apnea. The team focused on the brain structures called mammillary bodies that are located on the underside of the brain. They found that these bodies of the 43 patients were almost 20 percent smaller than those 66 patients that did not suffer from sleep apnea. The results of this study will be published in the June issue of the Neuroscience Letters.

Harper suggested that the continued drop in oxygen experienced by the patients might lead to brain injury. He also noted that the lack of oxygen during a sleep apnea episode could cause death to brain cells. "The reduced size of the mammillary bodies suggest that they've suffered a harmful event resulting in sizable cell loss. The fact that patients' memory problems continue despite treatment for their sleep disorder implies a long-lasting brain injury," he said.

The lead author on the study, Rajesh Kumar, an assistant researcher in neurology said that patients that suffer memory loss from other conditions such as Alzheimer's disease or alcoholism also show signs of shrunken mammillary bodies, so the finding from this particular study are very important. Physicians normally treat memory loss problems in patients that suffer from alcoholism with massive amounts of vitamin B1 or thiamine. They are suspecting that the doses given will help the dying brain cells to recover and enable the brain to use them again.

Harper and Kumar plan to study whether taking the supplemental B1 vitamin can help to restore the memory in patients with sleep apnea. The vitamin has been shown to move glucose into cells, which prevents the cells from dying from starvation of oxygen.

National Vital Statistics Report: U.S. Infant Mortality Rates

Author: Madeline Ellis

In an effort to understand the overall differences in infant mortality rates among different ethnic, age-specific and socioeconomic groups, the Centers for Disease Control and Prevention compiles information based on infant birth and death certificates for infants under one year of age in all 50 U.S. states as well as the District of Columbia, Puerto Rico, the Virgin Islands and Guam. The agency recently released this year's report, based on data from 2005, which presents infant mortality data by race and Hispanic origin of the mother, birth weight, period of gestation, sex of infant, plurality, maternal age, live-birth order, mother's marital status, mother's place of birth, infant age at death, and underlying cause of death.

According to the report, the average U.S. infant mortality rate was 6.86 infant deaths per 1,000 live births in 2005, which is virtually unchanged from the 6.78 statistic in 2004. However, there was a wide variation between ethnic groups. For example, for Asian or Pacific Islander (API) mothers, infant mortality rates were 4.89 deaths per 1,000 live births, 5.76 for non-Hispanic white mothers but 13.63 for non-Hispanic black mothers. Among Hispanics, rates ranged from 4.42 for Cuban mothers and 5.53 for Mexican mothers to 8.30 for Puerto Rican mothers.

Infant mortality rates were higher for infants who were born preterm or at low birth weight. Infants born at the lowest gestational ages and birth weights have a large impact on overall U.S. infant mortality. For example, more than half (55 percent) of all infant deaths in the United States in 2005 occurred to the 2 percent of infants born very preterm (less than 32 weeks of gestation). Infant mortality rates for late preterm infants (34-36 weeks of gestation) were three times those for term infants (37-41 weeks). The preterm-related infant mortality rate for non-Hispanic black mothers was 3.4 times higher and the rate for Puerto Rican mothers was 87 percent higher than the rate for non-Hispanic white mothers.

Female infants had a lower mortality rate (6.12 per 1,000 live births) than male infants (7.56 per 1,000 live births) in each racial group except American Indian or Alaska native (AIAN), but the difference was not significant. And, for multiple births, the infant mortality was 31.50, more than 5 times the rate of 6.00 for single births, accounting for 3 percent of all live births but 15 percent of all infant deaths in the United States. Multiple births are much more likely to be born preterm and at low birth weight than single births.

Infant mortality rates varied with maternal age; the highest death rates are for infants of teenage mothers (10.28) and mothers aged 40 years and over (7.85). The lowest rates are for infants of mothers in their late 20's and early 30's. Infant mortality rates were generally higher for first births than for second births, and then they generally increased as birth order increased. Overall, the infant mortality for first born (6.88) was 14 percent higher than for second born (6.02). The rate for fifth and higher order births (10.36) was 72 percent higher than the rate for second births, likely associated with older maternal age, multiple births, and lower socioeconomic status.

Infants of mothers who are not married were shown to be at higher risk for poor outcomes. In 2005, infants of married mothers had an infant mortality rate of 5.25 per 1,000 live births, 45 percent lower than the rate for infants of unmarried mothers (9.61). Marital status may be a marker for the presence or absence of social, emotional and financial resources. Also, the infant mortality for mothers born in the 50 states and the District of Columbia (7.26) was 43 percent higher than the rate for mothers born elsewhere (5.08). A variety of hypotheses may account for the lower infant rate, including possible differences in migration selectivity, social support, and risk behaviors. Also, women born outside the 50 states and the District of Columbia have been shown to have different characteristics than their U.S. born counterparts with regard to socioeconomic and educational status.

Approximately two-thirds of all infant deaths in 2005 (18,782 out of 28,384) occurred during the neonatal period (from birth through 27 days of age). The neonatal rate for infants of non-Hispanic black mothers (9.13) was more than twice those for AIAN (4.04), non-Hispanic white (3.71), API (3.37), Mexican (3.78), Central and South American (3.23), and Cuban mothers (3.05). The highest postneonatal mortality rates were for infants of non-Hispanic black (4.50) and AIAN (4.02) mothers, about twice the rate for non-Hispanic white mothers (2.05). Postneonatal mortality rates for Mexican (1.75), API (1.51), and Central and South American mothers (1.46) were lower than for non-Hispanic white mothers.

The three leading causes of infant death-congenital malformations (20 percent), low birth weight (17 percent), and sudden infant death syndrome (8 percent)-accounted for 44 percent of all infant deaths. The fourth and fifth leading causes were maternal complications (6 percent) and cord complications (4 percent). Together, the top five causes accounted for 54 percent of all infant deaths in the United States in 2005. The percentage of infant deaths that were ‘‘preterm-related'' increased from 34.6 percent in 2000 to 36.5 percent in 2005.

There were also additional statistics concerning infant mortality risks among education levels, levels of prenatal care, and for infants born to mothers who smoked during pregnancy. The infant mortality rate for mothers who completed 16 or more years of school was 4.15 in 2005. The rate was 51 percent lower than the rate for mothers who completed less than 12 years of education. The rate for mothers with a college degree was 3.60, 63 percent lower than the rate for mothers with less than a high school diploma (9.84).

The timing and quality of prenatal care received by the mother during pregnancy can be important to the infant's health and survival. In 2005, the mortality rate for infants of mothers who began prenatal care after the first trimester of pregnancy or had no care at all was 8.69 deaths per 1,000 live births, 40 percent higher than the rate for infants whose care began in the first trimester (6.20).

The infant mortality rate for infants of mothers who smoked was 11.44, 74 percent higher than the rate of 6.58 for non-smokers. The use of tobacco during pregnancy causes the passage of substances such as nicotine, hydrogen cyanide, and carbon monoxide from the placenta into the fetal blood supply. These substances restrict the growing infant's access to oxygen and can lead to adverse pregnancy and birth outcomes, such as low birth weight, preterm delivery, intrauterine growth retardation and infant mortality. Maternal smoking has also been shown to increase the risk of respiratory infections and inhibit allergic immune responses in infants.