Night shift work has long been linked to poor health. Now, a new study suggests that for women, such working patterns could increase the risk of cancer. Female night shift workers may be at greater cancer risk, researchers warn. Researchers found that women who engaged in long-term night shifts were almost a fifth more likely to develop cancer when compared with women who did not work such shifts. On looking at specific cancers, the researchers found that women who worked long-term night shifts were at even greater risk of skin cancer, breast cancer, and lung cancer. Study co-author Xuelei Ma, Ph.D., of the West China Medical Center at Sichuan University in China, and colleagues recently reported their findings in the journal Cancer Epidemiology, Biomarkers & Prevention. According to the Centers for Disease Control and Prevention (CDC), nearly 15 million people in the United States have irregular working patterns, including night shifts. Previous research has shown that night shift work can severely disrupt our circadian rhythm. This is the internal clock that regulates the body's physiological processes over a 24-hour cycle, and it primarily responds to light and dark in the environment. Shift work has been linked to a wealth of poor health outcomes, including obesity, heart disease, and some types of cancer. In the new study, Ma and colleagues sought to learn more about the link between long-term night shift work and cancer risk. Overall cancer risk increased by 19 percent The researchers came to their findings by conducting a meta-analysis of 61 studies. These included a total of 3,909,152 participants and more than 114,000 cancer cases. Subjects were from Asia, Australia, Europe, and North America. The team used these data to assess how long-term night shift work was associated with the risk of developing 11 cancer types. In a separate analysis, the researchers looked at whether long-term night shift work among female nurses was linked to the risk of six cancer types. Source
