Shift Work May Increase Risk of Type 2 Diabetes in Women

Rotating shift work is becoming very common in industrialized countries as most offices are working on 24/7 basis. Shift work not only makes you feel tired and irritable but also prone for incident of chronic diseases. Women who work a rotating(irregular) night shift may have higher risk of developing type 2 diabetes, particularly if they sustain that schedule for extended period of time, according to result of new study.

Prolonged Rotating Shift Work May Increase Risk of Diabetes in Women:

A study published in PLoS Medicine, peer-reviewed open-access journal, reports that women who work rotating shift work such as day shift, evening shift and three or more night shifts per month were associated with increased risk of type 2 diabetes when compared with women who did not rotate. Risk was greater if they followed same pattern over a longer period of time. Such women also showed tendency for excessive weight gain.

The researchers from Harvard School of Public Health (HSPH) analyzed data of women who were enrolled in two prospective cohort studies; Nurses’ Health Study I (NHS I, from 1988 to 2008) and Nurses’ Health Study II (NHS II, from 1989 to 2007) collectively. The baseline population for present study consisted of almost 238,381 U.S. women participants who answered questionnaire NHS I and NHS II. Participants who had diabetes, heart disease, stroke, or cancer at baseline were excluded from the study.

Investigators examined the possible link between duration of rotating night shift work and risk of type 2 diabetes over 18–20 years of follow-up. For study, rotating night shifts were defined as working at least three nights a month in addition to days and evenings in that month. Participants self-reported a diagnosis of type 2 diabetes through a supplemental questionnaire. The investigators updated information on risk factors for chronic diseases such as body weight, cigarette smoking, physical activity, family history of diabetes, menopausal status, and hormone use and dietary habit including alcohol consumption during follow-up.

The researchers observed that the longer women worked irregular night shifts, the greater their risk of developing type 2 diabetes. Women who worked irregular night shifts for three to nine years had 20% risk and who worked nights for 10 to 19 years had a 40% risk of type 2 diabetes. Risk increased to 58% in women who worked night shifts for over 20 years. Plus such women showed tendency for excessive weight gain and obesity during the follow-up.

In secondary analysis when body weight was taken into consideration, risk of type 2 diabetes for women who worked rotating night shifts though reduced, but still present to some extent. These findings indicated that the relationship between night shift work and risk for type 2 diabetes was not completely explained by increased weight.

Findings of study are not confirmed in men and other ethnic groups and hence more researches are needed.

Irregular shift work interrupts eating and sleeping schedule of person. Such disturb lifestyle pattern disturbs ‘body circadian rhythms’, which play an important role in sugar metabolism. This may be the possible reason for the link between shift work and obesity and subsequently type 2 diabetes.

Frank B.Hu, professor of nutrition and epidemiology at HSPH, in Boston said, “This study raises the awareness of increased obesity and diabetes risk among night shift workers and underscores the importance of improving diet and lifestyle for primary prevention of type 2 diabetes in this high risk group,”

Adoption of healthy lifestyle modifications such as daily exercises, balanced diet, good sound sleep and reduction of stress are some of the good approaches to prevent risk of type 2 diabetes among shift workers.



Dr. Minakshi Welukar

I am Pune based medical doctor (M.B.B.S) and certified medical writer from InfocusRx, Hyderabad, working as a family physician and freelance medical writer for health magazines and websites. Five years of clinical experience faced me to handle variety of patients to get best possible results, keep up-to-date knowledge about new medicinal advances and build-up medical specialist and social contacts.

3 thoughts on “Shift Work May Increase Risk of Type 2 Diabetes in Women

  • February 26, 2013 at 4:13 am

    A woman’s risk of developing type 2 diabetes increases steadily with the years of shift work she puts in, the study found. Compared to nurses who worked days only, those who worked periodic night shifts for as little as three years were 20% more likely to develop type 2 diabetes, while those who clocked at least 20 years of shift work were nearly 60% more likely to develop the disease For more info check out

  • December 29, 2011 at 1:52 am

    Gestational diabetes occurs in approximately 3% of pregnant women, and approximately 60% of those women will develop NIDDM over the subsequent 20 years. In addition, there is a 90 % chance that a woman who has developed it with one pregnancy will develop it in a subsequent pregnancy. Women of childbearing age, therefore, deserve attention regarding prevention

  • December 25, 2011 at 10:09 am

    Sleep is so important and is something I think many people overlook.

    During sleep, the body’s production of the appetite suppressor leptin increases and the appetite stimulant, grhelin decreases. Research finds that the less people sleep (five hours or less), the more likely they are to be overweight or obese and prefer eating higher calorie foods since their food regulation has been altered.

    Other research has found that when healthy volunteers slept only 4 hours a night for 6 nights in a row, their insulin and blood sugar levels matched those seen in people who were in the developmental stages of diabetes.

    Another study found that women who slept less than 7 hours a night were more likely to develop diabetes than those who slept between 7 and 8 hours a night.

    -Mandy Seay, RD, LD


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