nicotine dependence, smoking, alcohol use, genome-wide scan and twinlinkage

Loukola et al Linkage of nicotine dependence and smoking behavior on 10q, 7q and 11p in twins with homogeneous genetic background. The Pharmacogenomics Journal (2008) vol 8, 209–219
Why do some people tolerate and become dependent upon smoking tobacco and others do not. It important to study the genetic determinants of smoking behavior and the key factor sustaining compulsive smoking, that is, nicotine dependence (ND). Loukola et al looked at the genetic background of smoking in a special study sample of twins, equivalent for early life events and for smoking from the nationwide twin cohort of the genetically unique population of Finland. The twins and their families were examined for extensive phenotype profiles and a genome-wide scan was performed to identify loci behind the smoking status, ND and the comorbid phenotype of ND and alcohol use in 505 individuals from 153 families. They replicated previous linkage findings on 10q (max logarithm of the odds (LOD) 3.12) for a smoker phenotype, and on 7q and 11p (max LOD 2.50, and 2.25, respectively) for the ND phenotype. The loci linked for ND also showed evidence for linkage for the comorbid phenotype. Their study provides confirmatory evidence for the involvement of these genome regions in the genetic etiology of smoking behavior and ND and for the first time associates drinking and smoking to a shared locus on 10q.
nicotine dependence, smoking, alcohol use, genome-wide scan, twin, linkage

preservatives, colours and hyperactive behaviour

There is a belief that preservatives and colour can cause or exacerbate hyperactive behaviour in children. One trial supported this view, the European Food Safety Authority was luke warm about the interpretation of the results.
Attention deficit hyperactivity is a multifactorial condition, treatment is centred on three main strategies.
Drugs
Behavioural therapy
Dietary modification
The first and the second offer the best success
Kemp in a review in the BMJ suggest that a trial period of eliminating colourings and preservatives is a worth while exercise. It is best if this is appropriately supervised and evaluated.
Kemp 2008 Food additives and hyperactivity BMJ vol 336, p1144

Changes in populations

I have long felt that our population is one that has survived massive upheavals over the last few hundred years, the black death, emigration, starvation, war and tuberculosis .There is little to support this , but there is an interesting paper written on fish which is heavily fished in Nature vol 452 pp 835-839..
Christian N. K. Anderson et al have written a paper in Nature ”Why fishing magnifies fluctuations in fish abundance “ showing that fished populations can fluctuate more than unharvested stocks. However, it is not clear why. They distinguish among three major competing mechanisms for this phenomenon, by using the 50-year California Cooperative Oceanic Fisheries Investigations larval fish record. First, variable fishing pressure directly increases variability in exploited populations. Second, commercial fishing can decrease the average body size and age of a stock, causing the truncated population to track environmental fluctuations directly. Third, age-truncated or juvenescent populations have increasingly unstable population dynamics because of changing demographic parameters such as intrinsic growth rates. They find no evidence for the first hypothesis, limited evidence for the second and strong evidence for the third. Therefore, in California Current fisheries, increased temporal variability in the population does notarise from variable exploitation, nor does it reflect direct environmental tracking. More fundamentally, it arises from increased instability in dynamics.
This is an empirical example of how selective harvesting can alter the basic dynamics of exploited populations, and lead to unstable booms and busts that can precede systematic declines in stock levels.
Maybe the culling of human populations has the same effect.
Anderson et al 2008, Why fishing magnifies fluctuations in fish abundance Nature vol 452 pages 835-839.

Molecular Biological differences between populations differences in north and south China.

The genetic make up of populations and even apparently similar races is not uniform. The exciting developments in mapping populations reveal all manner of varieties.
Fuzhong Xue et al report a molecular biological which analyses the presence of a significant boundary between the populations of north and south in China.. This had previously been indicated by archeological, anatomical, linguistic, and genetic data which suggested the presence of a significant boundary between the populations of north and south in China. However, the exact location and the strength of this boundary have remained controversial. In this study, the authors systematically explored the spatial genetic structure and the boundary of north–south division of human populations using mtDNA data in 91 populations and Y-chromosome data in 143 populations. Their results highlight a distinct difference between spatial genetic structures of maternal and paternal lineages. A substantial genetic differentiation between northern and southern populations is the characteristic of maternal structure, with a significant uninterrupted genetic boundary extending approximately along the Huai River and Qin Mountains north to Yangtze River. On the paternal side, however, no obvious genetic differentiation between northern and southern populations is revealed.
This indicates the static nature of female populations in the past. And supports the contention that mobility of males has led to population diversity.
Fuzhong Xue et al (2008) A spatial analysis of genetic structure of human populations in China reveals distinct difference between maternal and paternal lineages. European Journal of Human Genetics) 16, 705–717;

genes, obesity and a Chinese study

Ling Yang1, et al (2008) Potential association of INSIG2 rs7566605 polymorphism with body weight in a Chinese subpopulation European Journal of Human Genetics 16, 759–761
Herbert et al reported association with obesity of a common DNA variant rs7566605 at 10 kb upstream of the INSIG2 gene. Ling Yang analyzed rs7566605 polymorphism in 3125 Chinese in a cross-sectional study. They found no significant association of rs7566605 polymorphism with body mass index (BMI) and waist circumference among all participants (P=0.52). However, if geographic location is considered, the C/C genotype of rs7566605 was marginally associated with increased levels of BMI and risk of obesity among individuals living in Shanghai (P=0.06), indicating that the C/C genotype may contribute to obesity in certain subpopulation among Chinese under certain environmental settings.

infant malnutrition

During 2008 the Lancet has run a fascinating series of articles on malnutrition and deprivation. These are profound contributions to our understanding and knowledge.
There is of course correspondence coming in to the Lancet concerning these articles and reveal the complexities of straight forward and sensible ideas.
Bhutta at al Lancet 2008 vol 371 pp 417-40 wrote about the Intervention for maternal and child undernutrtion and survival.
Amongst the issues raised was the value of vitamin A supplements within 3 days of birth and subsequent survival. Quite separate was the issue of supplementation after 6 months.
Bhutta et al studied all available papers. The problems of interpretation appear to be multiple and include the quality of the studies. Also as pointed out by Sachdev Lancet vol371 p 1746 that there is a risk of ignoring negative or neural results only looking at positive results. As yet unpublished papers are also a problem.
There is no problem about the value of vitamin A supplementation for the 6 months plus infant, the value is real.
For the new born the value is uncertain. This raises the possibility that the newly born can be protected by stores coming directly from their mother in the womb.
There are differences between children in Africa and Asia in the prevalence of kwashiorkor. This affects 2.5% of 1-3 year olds in Malawi in the maize eating communities. These babies are liable to develop metabolic failure, heart failure rather than simple wasting.(Ndekha Lancet vol 371 p 1748 )
The basic problem is one of nutrition and available clean nutritious food.

Biofuels and wheat prices

Private Eye has an important article on Biofuels. ( Private Eye 16th May 2008 p 15 )
Papers and Health Journals are beginning to feel unease about the use of valuable land to grow crops to make these fuels. Last year the European Union decided to sell its remaining grain stocks at knockdown prices just before global grain prices doubled and the world faced its first serious food shortage for decades?
The EU has now been forced to become the world’s largest grain importer, buying in 18m tons of wheat at prices much higher than those it was selling for only a short time earlier.
The reason for this follows the criticism of the EU for piling up vast food mountains, consequent upon its protection of European farmers by buying their crops when prices fell below a certain level. The EU then paid further subsidies for those food mountains which were sold off to the Third World at rock-bottom prices, doing immense damage to the farmers of some of the poorest countries of the world, who could not compete with the EU’s dumping of its cheap surpluses.
In 2007, having changed from subsidising over-production and anticipating a bumper European harvest. Brussels decided to empty its warehouses, selling off millions of tons of grain for animal feed. Unfortunately, down came the rains, with disastrous effects on the harvest. Europe was thus forced to buy million tons of wheat at twice the price it had been at the start of the summer.
The price of a loaf of bread is now rising above £1, and wheat and other cereal prices have soared in the past year. One explanation is that, as China and India become richer, more of their people can afford to eat meat, and they must thus import more grain to feed their animals. Last year the imports of wheat by China and India, the world’s two largest wheat growers, scarcely rose.
By far the biggest increase in demand, came from the EU and America. US cereal consumption last year rose by 12 percent, almost entirely due to that country’s involvement with biofuels, using up no less than 30m tons of corn.
Biofuels cost 70 percent more energy to produce than they generate, laying waste to rainforests and adding to pollution . US farmers, receive a hefty subsidy to grow them, and the EU has decided that 10 percent of our transport energy comes from biofuels within 12 years. Every acre of land used to make biofuel is taken away from producing food.
In the EU alone it will be necessary to divert more than 30 percent of our grain-producing land to biofuel.
This diversion of crops into biofuels will affect the provision of food to poorer communities. Malnutrition is such a major problem for much of the world, to further aggravate this cannot be wise.

Little obesity in Central France

I have just returned from a holiday in the Auverne France. Fun and lots of good food.
A striking feature of both the cities and rural areas is the seemingly uncommon occurrence of the obesity which is so commonly seen in Britain. This includes school children .
There must be many reasons for this but amongst the possibilities are
1. The reverence which the French have for food and the slow pace of eating the evening meal. Over 2 hours are spent in eating, chatting and being. No preoccupation with glycaemic indices which is a cover up for fast food. Fast in and slowly released. Contrary to current thought here in the UK breakfast is a small meal.
2..The small proportion of food shop display space devoted to crisps and confectionary..
3. Perhaps a sensitivity to the charm of slimness as apposed to the swelter of obesity.
But whilst observation is not epidemiology it is still a strong tool.

Growth disorders, a useful book

Disorders of growth either too little or too much are of great importance to clinical nutritionists. This book is an important source of information in this field. Such a topic covers so many fields, social, nutritional, genetic , public health, emotional to mention but a few.
Growth is one marker of health within and between communities. Though why height matters is another discussion. Small men Nelson, Napoleon and others were not tall but very important in their field.

Growth disorders, Kelnar CJH, Savage MO, Saenger MO, Cowell CT 2nd edition
Hodder Arnold London

gut-brain-liver axis and glucose regulation

Wang et al 2008 Upper intestinal lipids trigger a gut-brain-liver axis to regulate glucose production Nature vol 452, 1012-1016
Thaler and Cummings 2008, Food Alert Nature vol 452, 941-42
Energy and glucose homeostasis are regulated by food intake and liver glucose production, respectively. The upper intestine has a critical role in nutrient digestion and absorption. Upper intestinal lipids inhibit food intake as well in rodents and humans by the activation of an intestine-brain axis..
Wang and her colleagues tested the hypothesis that upper intestinal lipids activate an intestine-brain-liver neural axis to regulate glucose homeostasis. Direct administration of lipids into the upper intestine increased upper intestinal long-chain fatty acyl-coenzyme A (LCFA-CoA) levels and suppressed glucose production
Co-infusion of the acyl-CoA synthase inhibitor triacsin C or the anaesthetic tetracaine with duodenal lipids abolished ihe inhibition of glucose production, indicating that upper intestinal LCFA-CoAs regulate glucose production in the preabsorptive state.
Subdiaphragmatic vagotomy interrupts the neural connection between the gut and the brain, and blocks the ability of upper intestinal lipids to inhibit glucose production.
Direct administration of the N-methyl-D-aspartate ion channel blocker MK-801 into the fourth ventricle or the nucleus of the solitary tract where gut sensory fibres terminate abolished the upper-intestinal-lipid-induced inhibition of glucose production.
Hepatic vagotomy negated the inhibitory effects of upper intestinal lipids on glucose production.
Upper intestinal lipids activate an intestine-brain-liver neural axis to inhibit glucose production, a pathway that regulates glucose homeostasis.

Plastic food containers

Plastics are an omnipresent part of our food bought in shops or supermarkets. These are varied in Chemistry. Hopefully now most are recycled . Most of the plastic for recycling is carried to Hong Kong or China and the remainder is processed in the UK.
Vilified as they are, plastic containers are important in the transport and preservation of foods. Whereas 50% of food in India is wasted by the time it comes to be sold, the figure for plastic covered food is 3%
This topic is well aired in an article by Sam Knight in Financial Times Weekend Magazine April 26-27 , 2008 pages 15 to 22
Polyethylene terephthalate (PET) Fizzy drink and water bottles and salad tray's
High density polyethylene (HDPE) Milk bottles, bleach, cleaners and most shampoo bottles
(Linear) Low density polyethylene (LDPE)Carrier bags, bin liners and packaging films. Same molecule as HDPE, but less dense structure increases flexibility
Polypropylene (PP) Margarine tubs, and microwaveable meal trays
Polystyrene (PS) Yoghurt pots, foam burger boxes, egg cartons, plastic cutlerj and packaging for electronic goods and toys

Variations in life expectation

Christopher Cladwell has written an illuminating article in Financial Times April 26,27th 2008 p 13 discussing the wide expectation of life in the developed world.
Since 1983 life expectancy has declined for women in hundreds of US counties, most of them in the south, and for men in a dozen counties.
. In post-communist Russia men die at about the age of 59, largely related to alcohol. In Namibia the lifespan has dropped 10 years since independence in 1990 due to AIDS.
But since US life expectancy continues its modest rise (from 77.8 years in 2003 to 77.9 in 2004)
Life expectancy fell among poor US men in the early 1960s, for unknown reasons, and in the late 1980s, probably because of Aids and crack cocaine.
Where US healthcare and hygiene work, they are incomparably the best in the world. The 10m healthiest Americans have “one of the highest levels of life expectancy on record -three years better than Japan for females and four years better than Iceland for males”. Asian females in Bergen County, New Jersey, can expect to live an astounding 91 years. But the mortality rates of poor Appalachian whites resemble those of Panama or Mexico.
That is mortality inequality. In 1980 the US rich lived 2,8 years longer than the poor (75.8 versus 73); today they live 4.5 years longer (79.2 versus 74.7).
In Glasgow Scotland men in Glasgow’s pleasant East Dunbartonshire suburbs lived on average to be 81; in Calton, where 60 per cent of residents were unemployed, the life expectancy for men was 54,
Despite the conquest of contagious diseases in the early 20th centur and the reduction in heart-attack deaths in the past four decades.
A recent book by the journalist Bill Bishop, The Big Sort,” shows how like-minded Americans have congregated according to similarities in education, political ideology, wealth and various other attributes.
New Yorkers live longer not because they are doing different things than in 1990 but because they are a different set of people. Certain people have moved in -disproportionately young, employed elites with health insurance, good diet habits and health club memberships. Others have moved out.
Published online by the journal PLoS Medicine: Http:j/medicine, plosjou rnals. orgiperlservi Trequest =mdex-fitml&issn=1549-l676 ** Houghton-Mifflin, $25