Miriam Garland

Physical Activity, Body Mass Index, and Ovulatory Disorder Infertility

Few studies have examined whether activity and adiposity levels typical of American women affect their risk of ovulatory disorder infertility, and none has examined moderate and vigorous intensity exercise separately. We investigated these associations in the Nurses’ Health Study II, comparing prospectively collected data on adiposity and activity for 830 cases of incident ovulatory infertility and 26,125 pregnancies. We observed a U-shaped association between body mass index (BMI) and relative risk of ovulatory infertility, with increased risk for BMI below 20.0 or above 24.0 kg/m2. On the basis of the BMI distribution of U.S. women, these findings suggest that 12% (95% confidence interval = 7–20%) of ovulatory infertility in the U.S. may be attributable to underweight (BMI <20.0) and 25% (95% CI = 20–31%) to overweight (BMI ≥25.0). An increase in vigorous activity (but not moderate activity) was associated with reduced relative risk of ovulatory infertility. Each hour per week of vigorous activity was associated with a 7% (95% CI = 4–10%) lower relative risk of ovulatory infertility. After adjustment for BMI, a 5% (95% CI = 2–8%) reduction in relative risk per hour of weekly activity remained. These data suggest that, among American women, more ovulatory infertility is attributable to overweight and a sedentary lifestyle than to underweight and overexertion.

Randomized trial of vitamin supplements in relation to vertical transmission of HIV-1 in Tanzania.

Background: Observational studies suggest that poor nutritional status among HIVinfected pregnant women is associated with a higher risk of vertical transmission of HIV. Methods: We randomized 1083 pregnant women infected with HIV‐1 in a doubleblind, placebo‐controlled trial to examine the effects of supplements of vitamin A and/or multivitamins (excluding vitamin A) using a 2‐x‐2 factorial design. We report the effects of the supplements on HIV infection defined using polymerase chain reaction (PCR), or death up to 6 weeks postpartum. Results: Of babies in the multivitamin arm 38, (10.1%) were HIV‐positive at birth compared with 24 (6.6%) in the no‐multivitamin arm (relative risk [RR] = 1.54; 95% CI, 0.94‐2.51; p = .08). Of babies born to mothers in the vitamin A arm, 38 (10.0%) were HIV‐positive at birth compared with 24 (6.7%) in the no‐vitamin A arm (RR, 1.49; 95% CI, 0.91‐2.43; p = 0.11). Neither multivitamins nor vitamin A had an effect on HIV status at 6 weeks among those who were HIV‐negative at birth (RR = 1.04; 95% CI, 0.65‐1.66; p = 0.88) and (RR = 1.30; 95% CI, 0.80‐2.09; p = .29, respectively). Similarly, neither supplement was associated with being either HIVinfected or dead at birth (RR, 0.98; 95% CI, 0.76‐1.27; p = .89 and RR, 1.01; 95% CI, 0.78‐1.31; p = .95, respectively. A beneficial effect of multivitamins on birth weight was limited to babies who were HIV‐negative at birth; babies in the multivitamin arm weighed +94 g more compared with those in the no‐multivitamin arm (p = .02). Among babies who were HIV‐positive at birth, the corresponding difference was ‐31 g (p = .82). Conclusions: Vitamin A and multivitamins did not affect the risk of vertical transmission of HIV in utero nor during the intrapartum and early breastfeeding periods. Multivitamins resulted in a significant improvement in birth weight of babies who were HIV‐negative at birth but had no effect among those who were HIV‐positive. The effect of vitamin supplements on HIV transmission through breastfeeding and on clinical progression of HIV disease is yet to be ascertained.

Antioxidant micronutrients and breast cancer.

We reviewed epidemiologic evidence on the relationship between four antioxidant micronutrients (vitamin A, vitamin C, vitamin E, and selenium) and breast cancer risk. Available data support a modest protective effect of vitamin A, although more studies are needed to examine further this association and to assess the relative contributions of preformed vitamin A (retinol) and carotenoids. In addition, the possibility that some other component of vitamin A-rich foods may account for this observed association should be explored. Data on the relationship between vitamins C and E and breast cancer risk are limited and inconsistent, and further information is necessary. A substantial body of evidence indicates a lack of any appreciable effect of selenium intake on breast cancer risk, at least within the range of human diets. Future observational studies should ideally be prospective in design, as prospective studies are less prone to selection and recall bias than are case-control studies, and should address methodologic issues such as confounding by other micronutrients and appropriate storage conditions of blood specimens. Although hypotheses relating micronutrient intake to risk of breast cancer should be tested in randomized trials, ethical and logistical constraints make these studies difficult to perform.

Antioxidants and progression of human immunodeficiency virus (HIV) disease

Abstract HIV infection is thought to lead to increased oxidative stress which may in turn lead to faster progression of HIV disease. Therefore, antioxidants may have a role in the treatment of HIV disease. We review the data on the relations of selected antioxidants to HIV disease progression. Results from observational epidemiologic studies suggest that vitamin A deficiency may accelerate HIV disease progression. In observational studies conducted among vitamin A replete populations, associations between intake or status of vitamin A (both preformed vitamin A and s-carotene) and HIV disease progression have been less consistent. Available data from intervention studies are not entirely consistent with a beneficial effect of supplementation with preformed vitamin A or s-carotene. The relations of vitamins C and E to HIV disease progression have been examined in a small number of epidemiologic studies; results from such studies are compatible with a protective effect of high intakes or levels of these vitamins. In two prospective studies, low selenium levels were found to be associated with an increased risk of progression of HIV disease. Available epidemiologic data are consistent with a protective effect of multivitamin (or multivitamin-mineral) supplements, preparations which typically include several of the above antioxidants. Finally, limited epidemiologic data support a protective role of N-acetylcysteine (NAC) in HIV disease. Many studies conducted to date have been observational prospective studies; the interpretation of such studies is problematic, however, given the possibility of confounding by infection duration and other factors. Thus, well designed randomized trials are essential to properly investigate the role of antioxidants, particularly vitamin E, vitamin C, selenium, and NAC, in HIV disease. Such trials are urgently needed since dietary administration of antioxidants to HIV infected persons would be an inexpensive intervention appropriate for the developing world.