High intensity night lights have been linked to run-away obesity in women in urban areas.
A new study suggests intense night lights, associated with 24-hour economic activities are contributing to obesity in women.
The study by, among others, the Nairobi-based International Livestock Research Institute (ILRI) used satellite data to map out night time light intensity.
The researchers then compared night light intensity and urbanisation to national obesity data in both women and men in Nigeria.
The findings show areas with high night light intensity to be more urbanised and with higher night time economic activities. Women residing in such areas were found to have higher rates of obesity compared to those in less lit areas. Published last month in the journal Economics & Human Biology, the study suggests most risky are intense night lights such as found in entertainment joints.
Others are supermarkets, manufacturing units, airports, security zones and people living near security lights.
Intense night lights affect the production of melatonin, a hormone that helps regulate the human sleep cycle – the state of sleep and wakefulness.
The study says intense night lights exposure tends to interfere with the production and effects of melatonin much more in women than in men.
“This is seen to lead to more excessive body mass in women than in men,” says the study. Locally, the Kenya Country Management Unit of the World Bank had earlier linked high night light intensity in Kenyan cities to higher levels of economic activities.
Using data from the US Defense Meteorological Satellite Programme, the team successfully showed Nairobi, Kiambu, Nakuru and Mombasa in that order, to have the highest night light intensity in Kenya. The team also managed to show that these towns also had highest rates of economic activities measured by the respective gross domestic product.
The study showed counties whose night lights intensity is growing fastest in Kenya to be Siaya, Elgeyo Marakwet and Tharaka Nithi.
“The sum of lights has grown seven-fold in Siaya, five-fold in Tharaka Nithi and Elgeyo Marakwe since the turn of the century,” it says.
Kenya has in recent times reported high rates of obesity, especially among women. While night lights may not be the only cause, regions with highest levels of female obesity are likely to be highly lit. The rate of obesity in the counties in Kenya vary by more than five-fold between regions, ranging from less than 15 per cent in northern Kenya to over 45 per cent in cities and Central region.
Two-thirds of all obese women live in 10 counties, with the top three being Nairobi with 216,745 cases, Kiambu (101,365) and Mombasa (71,728).
In a mid-term strategic plan review, the Ministry of Health says at least one in every seven women is overweight or obese. The review was carried out in collaboration with the World Health Organisation (WHO) last year.
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