Medical Matters: Christmas is a time for candles. Long before the advent of electricity, Christmas trees were decorated with lit candles, which must have posed quite a fire hazard. The Christmas tradition of lighting candles and placing them in house windows on Christmas Eve - as a welcome to Jesus - lives on, especially in rural parts. And Mary Robinson, as President of Ireland, invoked the practice of displaying candles as a welcome home to the scattered diaspora of the time, writes Dr Muiris Houston.
The candle industry is not just driven by the Christmas market. With the use of scented candles, both as part of aromatherapy practice and as "de-stressing" agents, the market for candles is now year-round. The scents are quite magical - lavender, pine and ocean mist candles are very pleasant to sniff.
But at the risk of dampening your Christmas celebrations, candles are not without a potential health hazard. A number of research studies have found that candles with lead wicks can give off toxic emissions. One study, by researchers at the University of Michigan, found that such candles gave off emissions that exceeded US Environmental Protection Agency guidelines for outdoor use. Another, published in the Journal of the American Medical Association, found that smoke from some candles contained high lead levels.
The Consumer Product Safety Commission in the US tested a range of candles last year. It found that 40 per cent of candles on the market used metal wicks; of these up to 10 per cent produced high lead levels.
Lead is particularly hazardous to young children, so the finding that some candles release five times the amount considered dangerous for children under six is a source of concern.
Children exposed to high amounts of lead over a period of time can develop brain and central nervous system problems. Inhaling, and especially ingesting, lead has been shown to produce serious illness. In the past, toy soldiers coated in lead paint were chewed by small children. More recently, the change to unleaded fuel has been largely driven by fears that exhaust fumes from vehicles had been the source of elevated blood lead levels in children living close to major roads and in urban areas. A child who has eaten lead may show signs of brain damage in the form of irritability, drowsiness, convulsions and, if untreated, eventual coma. A colicky type of abdominal pain is also common and indeed a plain X-ray of the tummy may show lead fragments in the gastrointestinal system.
The level of lead in the blood is a guide to the severity of lead poisoning. Lead affects the function of blood cells and can also produce anaemia. In chronic poisoning, lead can interfere with the growing of a child's bones.
Treatment of a poisoned child is aimed at removing lead from the body. Agents which chelate (bind to) lead are used. EDTA and penicillamine mop up lead by forming non-toxic lead compounds, which are then excreted.
A child exposed to lead fumes is unlikely to develop a full-blown case of lead poisoning such as that described above. But the effects of chronic exposure to airborne lead can be more subtle, involving changes in a child's behaviour and learning abilities which can be difficult to assess.
Perhaps not surprisingly, given their central role in life, standards of candlemaking in the Middle Ages were quite strict. A 1381 English law required chandlers (makers and sellers of candles) to assure the quality of waxes and wicks. The penalties for a person selling bad wax varied from having the inferior candles "burnt before his doore", being put in a pillory, or even exile. Given the relative absence of standards governing candle materials today, people should probably pay careful attention to what is in the candles they are buying. And if you are in the habit of burning candles on a regular basis, it is worth considering the following in order to cut down on candle smoke:
Do not burn candles with a shiny metal core in the wick unless you know it is lead free. Keep the wick trimmed to a quarter of an inch or so
Keep candles away from draughts
Buy candles from reputable sources
Know what is in the wax you are burning
I have probably waxed on sufficiently about candles; used with care, they should not be a cause of concern for readers this festive season. Have a happy and healthy Christmas.
Dr Muiris Houston can be contacted at mhouston@irish-times.ie. He regrets he cannot answer individual queries.