Influence of poverty upon health in PLoS Medicine

This week PLoS Medicine publishes a special collection of articles that aim to highlight the profound influence of poverty upon health, as part of the Council of Science Editors' Global Theme Issue on Poverty and Human Development (http://www.councilscienceeditors.org/globalthemeissue.cfm):

• African women with inadequate food supply are more likely to have high risk sex
• Personal safety concerns could thwart exercise targets for the poor

African women with inadequate food supply are more likely to have high risk sex

Women in Botswana and Swaziland who do not have enough food to eat are more likely to engage in selling sex and in other sexual behaviors that put them at risk of HIV infection.

These are the findings of a major study of over 2000 people by Dr Sheri Weiser (University of California San Francisco, USA) and her colleagues in the United States, Botswana, and Swaziland, reported in the international open access journal PLoS Medicine.

In many parts of sub-Saharan Africa, women have little control over food supplies but are expected to feed their children and other members of the household (such as elders). The researchers conducted their study to see whether women who lack food sell sex, become sexually involved with men of a different generation, or engage in other risky behaviors.

The researchers therefore studied the link between food insufficiency (not having enough food to eat over the previous 12 months), sex exchange (exchanging sex for money, food, or other resources over the previous 12 months), intergenerational sex, inconsistent condom use, and other measures of risky sex.

Nearly one in three women reported food insufficiency. After allowing for variables such as education and income, women in both countries who reported food insufficiency were nearly twice as likely to have used condoms inconsistently with a non-regular partner or to have sold sex as women who had had sufficient food. They were also more likely to have had intergenerational sexual relationships and to report a lack of control in sexual relationships.

These findings strongly suggest that protecting and promoting access to food may decrease vulnerability of women in sub-Saharan Africa to HIV infection.

In a related Perspective article, Professor Nigel Rollins (University of KwaZulu-Natal, Durban, South Africa), who was not involved in the study, says that "the message of the study is clear: in the absence of adequate food for oneself or one's family, individuals will forfeit long-term personal safety to survive today."

Professor Rollins says that these findings provide "an additional rationale, even obligation, to consider hunger alleviation as a central component of HIV prevention programmes."

Citation: Weiser SD, Leiter K, Bangsberg DR, Butler LM, Percy-de Korte F, et al. (2007) Food insufficiency is associated with high risk sexual behavior among women in Botswana and Swaziland. PLoS Med 4(10): e260.

http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0040260

Exercise is strongly promoted for the maintenance of good health – particularly as regards people on lower incomes, who are generally less physically active. However, new research published in PLoS Medicine suggests that one barrier to physical activity in low-income areas may be that people do not consider their environment safe enough to allow them to walk, cycle or take other forms of outdoor exercise.

Gary Bennett of the Harvard School of Public Health and colleagues worked with over 1000 people, mainly from ethnic minorities, in a low-income area of one US city, Boston. They asked them, “How safe do you feel walking alone in your neighbourhood?” They were allowed to choose from options such as “safe”, “a little unsafe” and “unsafe”. The same question was asked about walking alone in the daylight and walking alone after dark. The researchers also asked the people in their study to wear a pedometer for five days. This instrument measures the number of steps that the wearer takes. It is a much more accurate way of finding out about activity levels than asking people how much exercise they can remember taking. Previous research on this topic has had to rely on what people say they have done in the way of physical activity.

Four out of five people said they did feel safe during the day but there was no association between daytime safety and physical activity. This was the case for both men and women. However, two-thirds of the people in the study felt unsafe in the night-time. There was no association between perceived night-time safety and physical activity among men, but women who reported feeling unsafe at night took around 1000 fewer steps per day than other women. That amounts to around 20% less physical activity.

Even the women who felt safe at night were only taking around 5000 steps per day, around half of what the US Surgeon General recommends for good health. So all the women in the study would benefit from more physical activity. However, the much lower amount of activity of the women who felt unsafe does suggest that a perceived lack of safety is an important factor, which could increase the risks to their health. While the association between perceived safety and activity was not found in men and only applied to night-time safety, the authors argue that their findings provide some evidence that safety concerns can be a barrier to physical activity in low-income areas.

Citation: Bennett GG, McNeill LH, Wolin KY, Duncan DT, Puleo E, et al. (2007) Safe to walk? Neighborhood safety and physical activity among public housing residents. PLoS Med 4(10): e306.