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To investigate breast cancer risk in Hispanic and non-Hispanic White women, the authors conducted a population-based case-control study of New Mexican women during 1992-1994 using incident breast cancer cases aged 35-74 years and frequency-matched controls selected using random digit dialing. Activity type and weekly duration of usual nonoccupational physical activity were used to calculate weekly metabolic equivalent (MET)-hours of total and vigorous physical activity (> or =5 METs). Conditional logistic regression models were fitted to estimate the relative risk of breast cancer for levels of physical activity and to assess the difference in effects by ethnicity, body mass index, energy intake, and menopausal status. Vigorous physical activity was associated with reduced breast cancer risk in both Hispanic and non-Hispanic White women. Women in the highest category of vigorous activity had lower risk of breast cancer (adjusted odds ratio = 0.34, 95% confidence interval: 0.22, 0.51 for Hispanic; adjusted odds ratio = 0.60, 95% confidence interval: 0.41, 0.89 for non-Hispanic White women) compared with women reporting no vigorous physical activity. Both pre- and postmenopausal Hispanic women showed decreasing risk with increasing level of activity. Physical activity was protective only among postmenopausal non-Hispanic White women. The effects of physical activity were independent from reproductive factors, usual body mass index, body mass index at age 18, adult weight gain, and total energy intake.

The authors investigated the relation between children's pulmonary function and intake of fruits, vegetables, juices, and vitamins A, C, and E by examining cross-sectional data from 2,566 children in the Children's Health Study collected during 1997-1998. Low total vitamin C intake (< or =10th percentile) was associated with deficits in forced vital capacity for both boys and girls and with deficits in flows that were larger in girls (forced expiratory volume in 1 second (FEV1), -3.3%, 95% confidence interval (CI): -6.0, -0.5; forced expiratory flow between 25% and 75% of forced vital capacity (FEF(25-75)), -5.5%, 95% CI: -10.5, -0.3) compared with boys (FEV1, -2.3%, 95% CI: -4.8, 0.3; FEF(25-75), -2.4%, 95% CI: -7.4, 2.8). Low dietary vitamin E intake was associated with lower FEF(25-75) (boys: FEF(25-75), -8.9%, 95% CI: -14.2, -3.3; girls: FEF(25-75), -2.5%, 95% CI: -8.3, 3.7). Deficits in FEF(25-75) were associated with low dietary vitamin A intake in girls (FEF(25-75), -7.9%, 95% CI: -12.7, -2.8) and with low total vitamin A intake in boys with asthma (FEF(25-75), -15.6%, 95% CI: -27.6, -1.6). Low intakes of orange and other fruit juices, which were the largest source of vitamin C, were associated with deficits in forced vital capacity and FEV1 in boys. In summary, lung function levels were lower in children with inadequate dietary antioxidant vitamin intake.

To investigate the effects of dietary magnesium, potassium, and sodium on children's lung function, the authors examined cross-sectional dietary data and pulmonary function tests from 2,566 children aged 11-19 years who attended schools in 12 southern California communities during 1998-1999. During school visits, each child completed a health update questionnaire, a validated food frequency questionnaire, and spirometric lung function testing. Low magnesium and potassium intakes were associated with lower lung function. Girls with low magnesium intake had lower forced expiratory flow at 75% of the forced vital capacity (FEF 75 ) (-8.3%, 95% confidence interval: -14.8, -1.4) than did girls with higher intake; reductions were larger in girls with asthma (forced expiratory flow between 25% and 75% of the forced vital capacity (FEF 25 75 ) (-16.2%, 95% confidence interval: -22.7, -9.1) and FEF 75 (-24.9%, 95% confidence interval: -32.8, -16.1)) than in girls without asthma (FEF 25-75 (-2.0%, 95% confidence interval: -7.4, 3.8) and FEF 75 (-4.1%, 95% confidence interval: -11.3, 3.7)). Boys with low magnesium intake showed deficits in forced vital capacity (-2.8%, 95% confidence interval: -5.4, -0.2) compared with boys with higher intake. The effects of low magnesium intake did not vary substantially in boys with and without asthma. Among girls, low potassium intake was also associated with deficits in forced expiratory volume in 1 second (-2.7%, 95% confidence interval: -5.2, -0.1) and forced vital capacity (-2.4%, 95% confidence interval: -4.7, -0.1). In summary, low magnesium and potassium intakes were associated with lower lung volumes and flows.