Among a large cohort of women with viable singleton pregnancies who underwent elective repeat cesarean sections, more than a third of deliveries were performed before 39 weeks of gestation. As compared with deliveries at or after 39 weeks, deliveries before 39 weeks of gestation — even those during the last 3 days before week 39 — were associated with an increased risk of a composite primary outcome that included neonatal death, respiratory complications, need for mechanical ventilation, treated hypoglycemia, newborn sepsis, and admission to the neonatal intensive care unit.

Schistosoma japonicum has been successfully controlled in villages along Poyang Lake, the largest freshwater lake in China. In addition to synchronous chemotherapy for humans and cattle, successful interventions have included the removal of cattle from snail-infested grasslands, improvements in sanitation, and intensive health education. The use of such interventions has now been adopted as the national control strategy for China.

In this study, 1791 military veterans with poorly controlled type 2 diabetes were randomly assigned to receive either standard or intensive glucose control. Other cardiovascular risk factors were treated uniformly. The glycated hemoglobin goal was an absolute reduction of 1.5 percentage points in the intensive-therapy group. There was no significant difference between the two groups for the rates of major cardiovascular events, death, or microvascular complications.

Ambient oxygen tension falls with decreasing barometric pressure, limiting the ability of oxygen to diffuse into the blood. In this field study, the authors measured arterial oxygen tension in climbers on their ascent to and descent from the peak of Mount Everest. The oxygen tensions recorded are quite low and indicate that humans can function, when acclimatized, in environments with very low ambient oxygen tension.

In this large, prospective cohort study of Chinese adults in 2005, tobacco smoking was associated with increased mortality. The authors estimate that 673,000 deaths in China in 2005 were caused by smoking. The leading causes of smoking-related deaths were cancer, cardiovascular disease, and respiratory diseases.

A healthy 25-year-old brunette woman reports a 12-month history of skin depigmentation. She first noticed patches of skin whitening on her hips, followed by additional depigmented patches on her elbows, shins, upper eyelids, and lower chin. A dermatologist recently made a diagnosis of vitiligo and recommended a sunscreen but offered little hope for treatment. How should she be evaluated and treated?

A 57-year-old man was transferred to this hospital because of progressive cognitive decline. Before admission, he had a generalized seizure, after which he was confused, incoherent, and intermittently agitated; he was admitted to another hospital and transferred 5 days later. His wife reported that he had had episodes of confusion for the past 5 years and worsening memory loss and performance problems for the preceding 2 months. He had a history of cutaneous melanoma, alcohol and drug abuse, and occupational exposure to organic solvents. Magnetic resonance imaging of the brain revealed diffuse signal abnormalities in the white matter. A diagnostic procedure was performed.