A breed's history is responsible for a large number of problems as well as all the good things that it has been bred for. So it has been for the Labrador Retriever as well. This breed is still very young in evolutionary terms, it was only recognized for the first time by the UK Kennel club in 1903, and by the American Kennel club in 1917. During the development of any breed, you will have health issues. Sometimes these are caused by the development itself and sometimes caused by the genes carried over from one of the "origin" breeds.
The Lab's development started in the early 19th century when the Earl of Malmesbury imported a number of St John's dogs from Newfoundland (currently part of the province Newfoundland and Labrador in Canada) and started developing a retriever for hunting waterfowl. A number of ancestral lines emanating from this breeding program contain genes which cause things like hip dysplasia, luxating patella ( affecting the knee), progressive retinal atrophy, cataracts, corneal dystrophy and retinal dysplasia (affecting the eyes). Hereditary myopathy, a deficiency in type II muscle fibre etc.
Given a responsible breeding program these inherited defects can be eliminated, but like all good thing this takes time. Good breeders know which lines carry the genes that cause these problems, and do not use any of them in their breeding programs. Unfortunately not all breeders are that conscientious or responsible, there is no way that this can be policed. Probably the best that can be done by any individual is when you want to buy a puppy, contact your local kennel union or club, and ask for a list of good breeders that you can approach. They will normally know who the good breeders are, and they are as keen, if not more keen to get rid of any inherited problems than most.
The diversity of the gene pool available is also a factor to take into account. This diversity also needs to be built up over time, there is no possible way that any individual or organization for that matter can make a difference overnight.
Investigation is being done into things like hip dysplasia, and the findings are that there may be more than just genes that cause this condition. Too much stress put on a young dog's back could also be a factor, at this stage there is no telling to what extent each of these factors is responsible.
A dog's weight is also a contributing factor in a lab's overall health, These dogs tend to put on weight extremely quickly if they don't get the exercise that they need, specially if you are not controlling their diet. Obesity is common in this breed and this leads to heart problems. Just plain common sense should take this sort of problem off the list of things to worry about.
